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1.
Abstract

Percent body fat, ratings of perceived exertion and maximal oxygen consumption during a continuous running treadmill test were obtained on 127 high school female cross country runners. These young runners (x 15.6 yrs) were running approximately 25 miles per week at the time of testing. They had an average [Vdot]O2 max of 50.8 ml · min-1 and an HR max of 198.0 bpm. The mean percent body fat, as determined from hydrostatic weighing, was 15.4%. The onset of metabolic acidosis was estimated to occur at 78% of [Vdot]O2 max. A stepwise multiple regression with the 3000 meter run as the dependent variable indicated that max treadmill run time, weight relative [Vdot]O2 max and [Vdot] max entered the equation in that order, yielding an R of 0.67. Both HR and RPE increased with work intensity, but not at equal rates. These high school female runners had higher [Vdot]O2 max's than previously reported for this age group; however, they were considerably below these values reported for national caliber distance runners.  相似文献   

2.
Abstract

The objective of this study was to provide anthropometric, physiological, and performance characteristics of an elite international handball team. Twenty-one elite handball players were tested and categorized according to their playing positions (goalkeepers, backs, pivots, and wings). Testing consisted of anthropometric and physiological measures of height, body mass, percentage body fat and endurance ([Vdot]O2max), performance measures of speed (5, 10, and 30 m), strength (bench press and squat), unilateral and bilateral horizontal jumping ability, and a 5-jump horizontal test. Significant differences were found between player positions for some anthropometric characteristics (height and percentage body fat) but not for the physiological or performance characteristics. Strong correlations were noted between single leg horizontal jumping distances with 5-, 10-, and 30-m sprint times (r = 0.51–0.80; P < 0.01). The best predictors of sprint times were single leg horizontal jumping with the dominant leg and the distance measured for the 5-jump test, which when combined accounted for 72% of the common variance associated with sprint ability. In conclusion, performance abilities between positions in elite team-handball players appear to be very similar. Single leg horizontal jumping distance could be a specific standardized test for predicting sprinting ability in elite handball players.  相似文献   

3.
The aims of this study were to quantify the effects of factors such as mode of exercise, body composition and training on the relationship between heart rate and physical activity energy expenditure (measured in kJ?·?min?1) and to develop prediction equations for energy expenditure from heart rate. Regularly exercising individuals (n = 115; age 18?–?45 years, body mass 47?–?120?kg) underwent a test for maximal oxygen uptake ([Vdot]O2max test), using incremental protocols on either a cycle ergometer or treadmill; [Vdot]O2max ranged from 27 to 81?ml?·?kg?1?·?min?1. The participants then completed three steady-state exercise stages on either the treadmill (10?min) or the cycle ergometer (15?min) at 35%, 62% and 80% of [Vdot]O2max, corresponding to 57%, 77% and 90% of maximal heart rate. Heart rate and respiratory exchange ratio data were collected during each stage. A mixed-model analysis identified gender, heart rate, weight, [Vdot]2max and age as factors that best predicted the relationship between heart rate and energy expenditure. The model (with the highest likelihood ratio) was used to estimate energy expenditure. The correlation coefficient (r) between the measured and estimated energy expenditure was 0.913. The model therefore accounted for 83.3% (R 2) of the variance in energy expenditure in this sample. Because a measure of fitness, such as [Vdot]O2max, is not always available, a model without [Vdot]O2max included was also fitted. The correlation coefficient between the measured energy expenditure and estimates from the mixed model without [Vdot]O2max was 0.857. It follows that the model without a fitness measure accounted for 73.4% of the variance in energy expenditure in this sample. Based on these results, we conclude that it is possible to estimate physical activity energy expenditure from heart rate in a group of individuals with a great deal of accuracy, after adjusting for age, gender, body mass and fitness.  相似文献   

4.
Abstract

The purpose of this study was to determine the relationship between female distance running performance on a 10 km road race and body composition, maximal aerobic power ([Vdot]O2 max ), running economy (steady-state [Vdot]O2 at standardized speeds), and the fractional utilization of [Vdot]O2max at submaximal speeds (% [Vdot]O2max ). The subjects were 14 trained and competition–experienced female runners. The subjects averaged 43.7 min on the 10 km run, 53.0 ml · kg?1 · min?1 on [Vdot]O2max , and 33.9, 37.7, and 41.8 ml · kg?1 · min?1 for steady-state [Vdot]O2 at three standardized running paces (177, 196, and 215 m · min?1). The mean values for fractional utilization of aerobic capacity for these three submaximal speeds were 64.3, 71.4, and 79.3% [Vdot]O2max , respectively. Significant (p < 0.01) relationships with performance were found for [Vdot]O2max (r = ?0.66) and % [Vdot]O2max at a standardized speed (r = 0.65). No significant (p > 0.05) relationships were found between running performance and either running economy or relative body fat. As with male heterogeneous groups, trained female road racing performance is significantly related to [Vdot]O2max and % [Vdot]O2max , but not related to body composition or running economy. It was further concluded that on a 10 km road race, trained females operate at a % [Vdot]O2max similar to that of their trained male counterparts.  相似文献   

5.
Abstract

Since [Vdot]O2 max (ml/minute · kg body weight) is known to be the primary determinant of work capacity in weight-bearing exercise, the quantification of sex-specific factors influencing aerobic capacity is necessary if appropriate work capacity and endurance performance expectations and standards are to be developed for men and women. Yet, due to varying procedures and sample characteristics, large discrepancies exist among studies concerning the magnitude of the sex difference in [Vdot]O2 max. The purpose of this article is to provide an integrative review of the research comparing [Vdot]O2 max in men and women using the meta-analytic strategy proposed by Glass (1976). An overall estimate of the magnitude of the sex effect for each of three expressions of [Vdot]O2 max is provided. When removing the variability in aerobic capacity due to body size and body fatness, the magnitude of difference in [Vdot]O2 max between men and women is substantially reduced. When expressed relative to fat-free weight, the [Vdot]O2 max values of the males are, on the average, 12 to 15% higher than those of the females. Sex-specific differences in relative hemoglobin content may be responsible for a part of this remaining difference. However, a substantial portion of the sex difference in [Vdot]O2 max (ml/minute · kg fat-free weight) is probably attributable to gender-associated differences in level of physical activity/conditioning. The ability to clearly identify the sex-related components of aerobic capacity is an objective warranting further investigation.  相似文献   

6.
Abstract

The Yo-Yo intermittent endurance test is frequently used to assess aerobic endurance performance in young soccer players but only the logical validity of the test has been shown to date. The main ai m of this study was to assess the criterion (i.e. association with maximal aerobic capacity, [Vdot]O2max) and construct validities of the test in young soccer players. A secondary aim was to examine possible shared variance of the Yo-Yo intermittent endurance test with other physical capacities. Sixty-two soccer players (age 13.7±0.5 years) from an Under-14 team participated. All players performed a battery of fitness tests to assess [Vdot]O2max, aerobic endurance performance (Yo-Yo intermittent endurance test), soccer dribbling endurance performance (Hoff dribbling test), and power performance (maximal vertical jump, 30-m sprint with 10-m split time). Results showed that the Yo-Yo intermittent endurance test was strongly correlated with [Vdot]O2max (r=0.63, P<0.001), thereby showing the test's criterion validity. Players with the best performance on the Yo-Yo intermittent endurance test had significantly higher [Vdot]O2max (P<0.001, large effect), and significantly better soccer dribbling endurance (P<0.001, large effect) and 30-m sprint times (P<0.05, medium effect). Logistic regression (r=0.79, P=0.0001) showed that Hoff dribbling test performance (explained variance=50.4%), [Vdot]O2max (explained variance=39.7%), and 30-m sprint time (explained variance=14.4%) were significant independent parameters contributing to performance on the Yo-Yo intermittent endurance test. Therefore, the Yo-Yo intermittent endurance test is a valid on-field aerobic endurance performance test for young soccer players, which can also be used to differentiate the maximal aerobic capacity, soccer dribbling endurance, and 30-m sprint performance of these players.  相似文献   

7.
Abstract

Muscular and aerobic capacity changes resulting from three months of wrestling training were examined in a group of normally active 7- to 9-year-old boys (N = 23) who competed in an intramural league tournament. A nontraining group of twenty-two boys of similar age, height, and weight served as control subjects, and were studied during the same period of time. The subjects were measured for body dimensions and skinfolds, and were given measures of back lift, leg press, and arm endurance (dips and chins). They were also measured for [Vdot]E max, [Vdot]O 2 max, and HR max employing a progressive treadmill protocol. Results of ANCOVA analyses indicated that (1) the mean improvements in [Vdot]E max (2.93 1·min ?1 ) and in [Vdot]O 2 max (+ 6.6 ml·kg ?1 ·min ?1 ) were not significantly greater than control (p > .05), nor was HR max; (2) arm endurance improved significantly over control (p < .05), as did the leg press, but the back lift was not improved significantly (p > .05); (3) no significant change occurred in height, weight, or in some of skinfolds (p > .05), but the wrestlers were less endomorphic and more ectomorphic than their control counterparts, and were judged essentially equivalent in mesomorphy. It is concluded that wrestling training in young boys improves strength, but does not improve aerobic capacity more than one would expect to see in normal children of similar age and size.  相似文献   

8.
Abstract

Eighty-seven female masters swimmers ranging in age from 20 to 69 were selected for a detailed study of their body composition and physiological responses at rest and during exercise. These women were then placed into two subsets, a highly trained group and a not highly trained group, on the basis of the frequency, duration, and intensity of swimming workouts. Significant differences were detected when comparing the highly trained and not highly trained subjects on measures of weight, body density, percent fat and lean body weight (p<.05). Significant differences which favored the highly trained group were also seen when comparing these same two groups for [Vdot]E max, [Vdot]O2 max (1/min), [Vdot]O2 max (ml·kg–1·min–1), [Vdot]O2 max (ml·kg·LBW–1·min–1), O2 pulse (ml·kg–1·beat–1), and O2 pulse (ml·kg·LBW–1). Both the highly trained and not highly trained swimmers were considerably lower in percent fat than previously reported data for normal untrained women of similar ages. In both groups, however, percent fat across age levels within each training group showed significant increases at approximately 40 years of age (p<.05). In the highly trained swimmers, [Vdot]O2 max (ml·kg–1·min–1) decreased at a mean rate of about 7% per decade, while in the not highly trained swimmers the decline was approximately 8% per decade. It appears that the rate of decline in [Vdot]O2 max in women with aging may be independent of training status.  相似文献   

9.
Abstract

The relative importance of body size, body composition, cardiovascular-respiratory capacity, and running speed in determining individual differences in performance on 600-yd run and mile run tests was investigated using data on 196 children, ages 7 to 12 years. A multivariate, multistage path model was developed in which height, % fat, [Vdot]O2 max (ml/kg FFW · min) and the 50-yd dash time were postulated as determinants of individual differences on the two distance-running tests. These four independent variables accounted for 71% and 66% of the variance in the 600-yd run and mile run, respectively. All four independent variables had significant associations with the two distance runs when the influence of the other independent variables was taken into account. The 50-yd dash time and % fat were found to be the most important determinants of both distance runs. It was concluded that determinants of the 600-yd run and mile run in elementary-school-age children are complex and that individual differences on these tests reflect a number of attributes in addition to cardiovascular-respiratory capacity.  相似文献   

10.
Abstract

The effect of caffeine ingestion on submaximal endurance performance of 15 females and 13 males was investigated. After completing a [Vdot]O 2 max test, each subject performed two submaximal cycling tests at approximately 75% of [Vdot]O 2 max to exhaustion. For the caffeine (C) trials, 300 mg of caffeine was added to 250 ml of decaffeinated coffee and ingested one hour prior to the exercise. The decaffeinated (D) trial involved consuming 250 ml of decaffeinated coffee an hour prior to the test. The C and D trials were administered randomly using a standard double blind design. Physiological parameters were monitored each 9, 10, and 11 minute intervals throughout each trial and averaged. As expected the [Vdot]O 2 (L · min ?1 ), [Vdot]E and work outputs (kgm) were significantly (p < 0.001) higher for the males than the females. All other variables, time to exhaustion, [Vdot]O 2 (ml · kg · min ?1 ), R, HR, and rating of perceived exertion (RPE) were not significantly (p > 0.05) different between the sexes for either the C or D trials. Time to exhaustion was 14.4 and 3.1% longer for the C trials for the females and males, respectively, however these increases were not significant (p > 0.05). Furthermore, there were no significant differences (p > 0.05) for any of the measured variables during successive 10 minute work intervals between the C and D trials for either sex. These results do not support the general use of caffeine in moderate amounts as an ergogenic aid for either males or females, but from a practical point it appears that caffeine may have an ergogenic effect on specific individuals.  相似文献   

11.
Abstract

The purpose of the study was to determine the effects of 15, 30, and 45 min of conditioning on maximum performance and cardiorespiratory fitness variables, body composition, pulmonary function, and serum lipids. Subjects, ages 20 to 35, were 59 inmates at a California state prison. The conditioning included running and walking and was performed three days/week at approximately 85 to 90% max HR for 20 weeks. The distance covered per exercise session was approximately 1.75, 3.25, and 5.1 miles for the 15-, 30-, and 45-min groups, respectively.

Improvements in treadmill performance time. [Vdot]O2 max, max O2 pulse, diastolic blood pressure, and total skinfold fat were proportional to duration of the training session; i.e., the subjects training in the longer duration sessions showed the greater improvements. The control group showed no significant change during the same period. Compared to the control group, the 15-min group made significant reductions in resting HR, total skinfold fat, percent fat, and waist girth and increases in [Vdot]O2 max, max O2 pulse,[Vdot]E max, and treadmill performance time. Vital capacity, FEV1.0, and % FEV1.0 remained relatively unchanged in all four groups, as did serum cholesterol and triglycerides. The 45-min group improved significantly more than the 15-min group in treadmill time, [Vdot]O2 max, max O2 pulse, resting systolic and diastolic blood pressures, and percent fat. In general, comparisons between the 15- and 30-min groups and between the 30- and 45-min groups failed to yield statistically significant differences.  相似文献   

12.
Abstract

The purpose of this study was to investigate selected physiological changes that occurred with distance training in teenage females. Two groups of untrained teenage females were matched on [Vdot]O2 max, percent utilization of [Vdot]O 2 @ 9.66 km/hr, peak heart rate, and percent body fat. One group served as control (n = 9) while the other (n =10) underwent a 20-week training program designed to gradually increase the subjects' average mileage from 0 to 32.2 km per week. At the end of the 20 weeks, a MANOVA revealed significant mean differences within the trained group and no significant mean differences within the control group. The univariate analysis revealed that significant (p <0.05) mean differences found within the training group were for [Vdot]O 2 max (45.1 vs. 49.3 ml · kg –1 · min –1 ), percent utilization of [Vdot]O 2 @9.66 km/hr (76.5% vs. 67.5%), and economy VO 2 @9.66 km/hr (34.5vs.33.2 ml · kg –1 · min –1 ). Of the variables which exhibited significant training effects, percent utilization of [Vdot]O 2 max showed the greatest relative change, a 12.2% decrease, with [Vdot]O 2 max showing a 9.3% increase. The posttest results were similar to the research literature for training effects found for males and other age groups.  相似文献   

13.
Abstract

The bradycardia effect of a 10-week jogging program was studied in 13 previously sedentary middle-aged subjects (seven women and six men). This response during standardized submaximal treadmill walking and leg cycling was related to changes in cardiac output ([Qdot]), stroke volume (SV), and arteriovenous oxygen differences (a-vO2 diff). Heart rate (HR) response was also studied during load carrying and arm cycling tasks, and a [Vdot]O2 max test was administered. All tests were repeated posttraining. The posttraining increases in [Vdot]O2 max (ml/kg × min-1) were 19.7% and 14.8% for the men and women respectively. Training also produced significant reductions in submaximal HR and Q during treadmill and leg cycling exercise. A-vO2 diff rose, while there were no changes in [Vdot]O2 during the submaximal work tasks, suggesting either altered blood flow or a greater capacity to utilize O2 by the working muscle. Both men and women showed significant reductions in HR during the arm cycling and load carrying as well. These data suggest that a jogging program can alter cardiovascular function in tasks other than running. The magnitude and direction of change showed no sex differences; therefore, it was also concluded that there are no differences in the trainability of previously sedentary middle-aged men and women.  相似文献   

14.
Abstract

Nine lean (6.9%–19.3% body fat) and 12 moderately obese (31.6%–42.3% body fat) college men were compared in terms of maximum aerobic power, resting pulmonary function tests, and selected respiratory variables during a progressive bicycle ergometer test. The [Vdot]O2 max (1/min) was slightly higher (p > .05) in the obese group but significantly lower (p < .05) when expressed in cc/kg min or cc/kg FFBW min. Lower RV, ERV, and FRC data were observed in the obese group, but no differences were documented for tests of FVC or MVV. Higher values were displayed by the obese subjects for [Vdot]E, [Vdot]A, and tidal volume at rest and during each submaximal intensity of bicycle work. These observations appeared to be due to the obese subjects' higher energy expenditures, since no differences were documented in the ventilation equivalent ([Vdot]E/[Vdot]O2), the [Vdot]A/[Vdot]E ratio, or breathing frequency. It was concluded, within the limitations of the study, that the hypothesis of respiratory dysfunction in the moderately obese was not supported.  相似文献   

15.
Abstract

Mountain biking is a popular recreational pursuit and the physiological demands of cross-country style riding have been well documented. However, little is known regarding the growing discipline of gravity-assisted downhill cycling. We characterised the physiological demands of downhill mountain biking under typical riding conditions. Riding oxygen consumption ([Vdot]O2) and heart rate (HR) were measured on 11 male and eight female experienced downhill cyclists and compared with data during a standardised incremental to maximum ([Vdot]O2max) exercise test. The mean [Vdot]O2 while riding was 23.1 ± 6.9 ml · kg?1 · min?1 or 52 ± 14% of [Vdot]O2max with corresponding heart rates of 146 ± 11 bpm (80 ± 6% HRmax). Over 65% of the ride was in a zone at or above an intensity level associated with improvements in health-related fitness. However, the participants’ heart rates and ratings of perceived exertion were artificially inflated in comparison with the actual metabolic demands of the downhill ride. Substantial muscular fatigue was evident in grip strength, which decreased 5.4 ± 9.4 kg (5.5 ± 11.2%, P = 0.03) post-ride. Participation in downhill mountain biking is associated with significant physiological demands, which are in a range associated with beneficial effects on health-related fitness.  相似文献   

16.
Abstract

Previous investigators have yielded conflicting results in testing the hypothesis that the use of toe clips during bicycle ergometry produces a higher maximal oxygen uptake ([Vdot]O 2 max) than testing without toe clips. Eight men, four competitive cyclists and four competitive distance runners volunteered to participate in three randomized [Vdot]O 2 max tests: 1) a treadmill running lest, 2) a bicycle ergometer test using standard toe clips, and 3) a test on the same ergometer without toe clips. The highest mean [Vdot]O 2 max was observed in the treadmill condition as expected. However, no statistically significant difference in mean [Vdot]O 2 max or performance time was observed between the toe-clip and no toe-clip conditions. Based on these results, the research hypothesis was rejected and no favorable physiological effect may be attributed to the use of toe clips.  相似文献   

17.
Abstract

The purpose of this investigation was to evaluate and quantify physiological differences among groups of distance runners. The subjects included 20 elite distance runners (8 marathon, 12 middle-long distance) and 8 good runners. Working capacity and cardiorespiratory function were determined by submaximal and maximal treadmill tests, and body composition by hydrostatic weighing. The variables studied were maximum oxygen uptake ([Vdot]O2 max), [Vdot]O2 submax, lactic acid submax, lean body weight, and fat weight. MANOVA showed that the good runners differed from the elite runners (p < 0.01) and the elite marathon runners differed from the elite middle-long distance runners (p < 0.05). Discriminant analysis showed that both functions were significant. The first was a general physiological efficiency factor that separated the good and elite runners. The second separated the elite marathon and middle-long distance groups. The second function showed that the marathon runners had lower lactic acid submax values. The middle-long distance runners had higher [Vdot]O2 max values. Classification analysis was used to evaluate the accuracy of the discriminant analysis; 80% of the elite runners were correctly classified as marathon or middle-long distance runners. The discriminant functions were used to develop a multivariate scaling model for evaluating distance runners. Two premier runners, one marathoner (F. Shorter) and one middle-long distance runner (S. Prefontaine), were found to be at the extremes of the scale. The data showed that the discriminant functions provided a valid model for evaluating differences among elite distance runners.  相似文献   

18.
Abstract

The purpose of this study was to assess the relationships among ventilatory threshold T(vent), running economy and distance running performance in a group (N=9) of trained experienced male runners with comparable maximum oxygen uptake ([Vdot]O2 max). Maximal oxygen uptake and submaximal steady state oxygen uptake were measured using open circuit spirometry during treadmill exercise. Ventilatory threshold was determined during graded treadmill exercise using non-invasive techniques, while distance running performance was assessed by the best finish time in two 10-kilometer (km) road races. The subjects averaged 33.8 minutes on the 10km runs, 68.6 ml · kg -1 · min -1 for [Vdot]O2 max, and 48.1 ml · kg -1 · min -1 for steady state [Vdot]O2 running at 243 meters · min -1. The T(vent) (first deviation from linearity of [Vdot]E, [Vdot]CO 2 ) occurred at an oxygen consumption of 41.9 ml · kg -1 · min -1. The relationship between running economy and performance was r = .51 (p>0.15) and the relationship between T(vent) and performance was r = .94 (p < 0.001). Applying stepwise multiple linear regression, the multiple R did not increase significantly with the addition of variables to the T(vent); however, the combination of [Vdot]O2 max, running economy and T(vent) was determined to account for the greatest amount of total variance (89%). These data suggest that among trained and experienced runners with similar [Vdot]O2 max, T(vent) can account for a large portion of the variance in performance during a 10km race.  相似文献   

19.
Abstract

Sixteen men were studied during 6-min bouts of motorized treadmill running at 230 m · min–1 and 0% and 4% grade to compare [Vdot]O2 while using freely chosen stride lengths (CSL) and stride lengths approximately 8% shorter (SSL) and longer (LSL) than CSL. The study also attempted to determine whether stride length variations of these proportions altered [Vdot]O2 differently at the two grades. CSL were greater (p<.05) at 0% than 4% with mean values of 133.5 and 131.5 cm, respectively. Two-way ANOVA (Stride x Grade) with repeated measures yielded significant F values (p<.05) for the main effects of both stride length and grade but not for interaction between the two factors. Mean [Vdot]O2 values were 44.95 and 56.80 ml · kg1 · min–1 at 0% and 4% grade, respectively. The Tukey w procedure was used for comparing the main effect means across both grades for the three stride lengths. These means were 50.94, 49.88, and 51.80 ml · kg1 · min–1 for SSL, CSL, and LSL, respectively, with the CSL mean significantly less than the SSL and LSL means (p<.05). Stride length variations of approximately ±8% did not alter [Vdot]O2 differently at the two grades, and although [Vdot]O2 for SSL and LSL was not different, [Vdot]O2 was significantly (p<.05) increased by 2.1% for SSL and 3.8% for LSL. Not all individual patterns followed the group norm, however, in that three subjects were more economical with short stride lengths and two were more economical with longer strides.  相似文献   

20.
Abstract

We assessed the agreement between maximal oxygen consumption ([Vdot]O2max) measured directly when performing the 20-m shuttle run test and estimated [Vdot]O2max from five different equations (i.e. Barnett, equations a and b; Léger; Matsuzaka; and Ruiz) in youths. The 20-m shuttle run test was performed by 26 girls (mean age 14.6 years, s = 1.5; body mass 57.2 kg, s = 8.9; height 1.60 m, s = 0.06) and 22 boys (age 15.0 years, s = 1.6; body mass 63.5 kg, s = 11.5; height 1.70 m, s = 0.01). The participants wore a portable gas analyser (K4b2, Cosmed) to measure [Vdot]O2 during the test. All the equations significantly underestimated directly measured [Vdot]O2max, except Barnett's (b) equation. The mean difference ranged from 1.3 ml · kg?1 · min?1 (Barnett (b)) to 5.5 ml · kg?1 · min?1 (Léger). The standard error of the estimate ranged from 5.3 ml · kg?1 · min?1 (Ruiz) to 6.5 ml · kg?1 · min?1 (Léger), and the percentage error ranged from 21.2% (Ruiz) to 38.3% (Léger). The accuracy of the equations available to estimate [Vdot]O2max from the 20-m shuttle run test is questionable at the individual level. Furthermore, special attention should be paid when comparisons are made between studies (e.g. population-based studies) using different equations. The results of the present study suggest that Barnett's (b) equation provides the closest agreement with directly measured [Vdot]O2max (cardiorespiratory fitness) in youth.  相似文献   

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