全文获取类型
| 收费全文 | 37398篇 |
| 免费 | 570篇 |
| 国内免费 | 150篇 |
专业分类
| 教育 | 26437篇 |
| 科学研究 | 4109篇 |
| 各国文化 | 311篇 |
| 体育 | 2806篇 |
| 综合类 | 44篇 |
| 文化理论 | 382篇 |
| 信息传播 | 4029篇 |
出版年
| 2021年 | 306篇 |
| 2020年 | 534篇 |
| 2019年 | 750篇 |
| 2018年 | 1538篇 |
| 2017年 | 1586篇 |
| 2016年 | 1377篇 |
| 2015年 | 652篇 |
| 2014年 | 840篇 |
| 2013年 | 6547篇 |
| 2012年 | 869篇 |
| 2011年 | 1131篇 |
| 2010年 | 903篇 |
| 2009年 | 777篇 |
| 2008年 | 899篇 |
| 2007年 | 960篇 |
| 2006年 | 674篇 |
| 2005年 | 681篇 |
| 2004年 | 695篇 |
| 2003年 | 619篇 |
| 2002年 | 611篇 |
| 2001年 | 632篇 |
| 2000年 | 626篇 |
| 1999年 | 619篇 |
| 1998年 | 341篇 |
| 1997年 | 367篇 |
| 1996年 | 418篇 |
| 1995年 | 367篇 |
| 1994年 | 325篇 |
| 1993年 | 320篇 |
| 1992年 | 446篇 |
| 1991年 | 440篇 |
| 1990年 | 497篇 |
| 1989年 | 481篇 |
| 1988年 | 427篇 |
| 1987年 | 392篇 |
| 1986年 | 402篇 |
| 1985年 | 479篇 |
| 1984年 | 409篇 |
| 1983年 | 384篇 |
| 1982年 | 309篇 |
| 1981年 | 302篇 |
| 1980年 | 260篇 |
| 1979年 | 413篇 |
| 1978年 | 330篇 |
| 1977年 | 317篇 |
| 1976年 | 262篇 |
| 1975年 | 227篇 |
| 1974年 | 235篇 |
| 1973年 | 242篇 |
| 1972年 | 192篇 |
排序方式： 共有10000条查询结果，搜索用时 156 毫秒
81.
The purpose of this study was to determine test-retest reliability for the 1-mile, 3/4-mile, and 1/2-mile distance run/alk tests for children in Grades K-4. Fifty-one intact physical education classes were randomly assigned to one of the three distance run conditions. A total of 1,229 (621 boys, 608 girls) completed the test-retests in the fall (October), with 1,050 of these students (543 boys, 507 girls) repeating the tests in the spring (May). Results indicated that the 1-mile run/walk distance, as recommended for young children in most national test batteries, has acceptable intraclass reliability (.83 less than R less than .90) for both boys and girls in Grades 3 and 4, has minimal (fall) to acceptable (spring) reliability for Grade 2 students (.70 less than R less than .83), but is not reliable for children in Grades K and 1 (.34 less than R less than .56). The 1/2 mile was the only distance meeting minimal reliability standards for boys and girls in Grades K and 1 (.73 less than R less than .82). Results also indicated that reliability estimates remained fairly stable across gender and age groups from the fall to spring testing periods, with the exception of the noticeably improved values for Grade 2 students on the 1-mile run/walk test. Criterion-referenced reliability (P, percent agreement) was also estimated relative to Physical Best and Fitnessgram run/walk standards. Reliability coefficients for all age group standards were acceptable to high (.70 less than P less than .95), except for Fitnessgram standards for 5-year-old girls on the 1-mile test for both fall and spring and for 6-year-old boys and girls on the 1-mile test administered in the spring. 相似文献
82.
83.
84.
D A Sedlock 《Research quarterly for exercise and sport》1991,62(2):213-216
This study was designed to examine the magnitude and duration of excess postexercise oxygen consumption (EPOC) following upper body exercise, using lower body exercise for comparison. On separate days and in a counterbalanced order, eight subjects (four male and four female) performed a 20-min exercise at 60% of mode-specific peak oxygen uptake (VO2) using an arm crank and cycle ergometer. Prior to each exercise, baseline VO2 and heart rate (HR) were measured during the final 15 min of a 45-min seated rest. VO2 and HR were measured continuously during the postexercise period until baseline VO2 was reestablished. No significant difference between the two experimental conditions was found for magnitude of EPOC (t [7] = 0.69, p greater than .05). Mean (+/- SD) values were 9.2 +/- 3.3 and 10.4 +/- 5.8 kcal for the arm crank and cycle ergometer exercises, respectively. Duration of EPOC was relatively short and not significantly different (t [7] = 0.24, p greater than .05) between the upper body (22.9 +/- 13.7 min) and lower body (24.2 +/- 19.4 min) exercises. Within the framework of the chosen exercise conditions, these results suggest EPOC may be related primarily to the relative metabolic rate of the active musculature, as opposed to the absolute exercise VO2 or quantity of active muscle mass associated with these two types of exercise. 相似文献
85.
86.
87.
88.
89.
The purpose of this investigation was to describe the morphological parameters that characterize elite age group divers. Comparisons are made to normative age group data from the Coquitlam Growth Study and the constancy of important characteristics from age group to age group is examined. Data were collected on 27 male and 28 female elite divers who participated in the 1990 North American Age Group Diving Championships. Body build, body composition and skinfold corrected diameters were determined from 36 anthropometric parameters and analysed by ANOVA, t-test and Phantom z-scores procedures. All age groups except the 14- to 15-year-old males were significantly (P < or = 0.05) shorter than their norms but recorded higher androgyny index values. The estimated relative muscle mass increased significantly (P < or = 0.05) with age for males at all ages (40.8-46.3%). The 16- to 18-year-old females had a significantly (P < or = 0.05) larger relative muscle component compared to the younger age groups (40.1-38.4%). When normalized for height, active tissue development of the extremities was comparable between the sexes except in the forearm. The results indicate that at all age levels short stature is an important characteristic for divers. Analysis of regional active tissue development provides further insight into sport-specific prerequisites for success at elite levels. 相似文献
90.