首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1028篇
  免费   15篇
教育   740篇
科学研究   41篇
各国文化   20篇
体育   101篇
综合类   1篇
文化理论   23篇
信息传播   117篇
  2021年   6篇
  2020年   14篇
  2019年   17篇
  2018年   21篇
  2017年   22篇
  2016年   24篇
  2015年   19篇
  2014年   31篇
  2013年   267篇
  2012年   27篇
  2011年   28篇
  2010年   23篇
  2009年   18篇
  2008年   22篇
  2007年   27篇
  2006年   22篇
  2005年   26篇
  2004年   20篇
  2003年   24篇
  2002年   21篇
  2001年   9篇
  2000年   20篇
  1999年   7篇
  1998年   9篇
  1997年   10篇
  1996年   12篇
  1995年   12篇
  1994年   13篇
  1993年   20篇
  1992年   16篇
  1991年   23篇
  1990年   14篇
  1989年   14篇
  1988年   13篇
  1987年   9篇
  1986年   15篇
  1985年   9篇
  1983年   11篇
  1982年   12篇
  1981年   13篇
  1980年   6篇
  1979年   15篇
  1978年   6篇
  1977年   4篇
  1976年   9篇
  1974年   4篇
  1973年   9篇
  1971年   4篇
  1970年   7篇
  1969年   4篇
排序方式: 共有1043条查询结果,搜索用时 62 毫秒
131.
The northern Wet Tropics rainforest of Australia was declared a world heritage site in 1988 and now supports an extensive tourism industry that attracts an estimated 2.5 million local and international visits annually. As part of the visitor experience, many sites include both environmental and cultural interpretation experiences, which range from static displays to one‐on‐one guided tours. This paper identifies visitor demand and level of satisfaction with the static signage and displays used at rainforest sites throughout the Wet Tropics. The research involves visitor surveys conducted in 2007 and 2008 and observations at a number of rainforest sites. The results indicate that visitors consider the level of interpretation to be adequate, but appear to use it poorly. While higher at commercial sites, visitor interest in reading the interpretation is very low at public sites. Overall, this article seeks to address whether the aims of nature‐based interpretation, including education and the influencing of attitudes and site behaviour, are being achieved.  相似文献   
132.
133.
The study compared the agreement, internal consistency, and measurement stability of the GE iDXA, BOD POD, and InBody 720. Body composition of 43 men and 37 women (31.4 ± 10.7 years; 90% Caucasian and 10% other) was assessed in triplicate using each method over two different days. Mean percent body fat (% BF) of the participants was different for all three machines (27.6 ± 10.0% [GE iDXA)] 25.6 ± 10.4% [BOD POD], and 21.3 ± 10.6% [InBody 720]; p < .05). The coefficient of variation for same day repeated measures was 1.06% (GE iDXA), 3.29% (BOD POD), and 2.97% (InBody 720). The coefficient of variation for 2-day repeated measures was 1.81% (GE iDXA), 4.61% (BOD POD), and 4.24% (InBody 720). The difference between the GE iDXA and BOD POD was within acceptable variability, while the InBody 720 significantly underestimated % BF. The internal consistency was highest for the GE iDXA, followed by the InBody 720, and then the BOD POD.  相似文献   
134.
Active drag force in swimming can be calculated from a function of five different variables: swim velocity, tow velocity, belt force, power output and exponent of velocity. The accuracy of the drag force value is dependent on the accuracy of each variable, and on the contribution of each variable to drag estimation. To calculate uncertainty in drag value, first the derivatives of the active drag equation with respect to each variable were obtained. Second, these were multiplied by the uncertainty of that variable. Twelve national age and open level swimmers were recruited to complete four free swimming and five active drag trials. The uncertainties for the free and the tow swim velocities, and for the belt force, contributed approximately 5–6% and 2–3% error, respectively, in calculation of drag. The result of the uncertainty of the velocity exponent (1.8–2.6) indicated a contribution of about 6% error in active drag. The contribution of unequal power output showed that if a power changed 7.5% between conditions, it would lead to about 30% error in calculated drag. Consequently, if a swimmer did not maintain constant power output between conditions, there would be substantial errors in the calculation of active drag.  相似文献   
135.
This study explored the extent to which teachers integrate environmental education and local environmental knowledge into the curriculum of a secondary school in the Okavango Delta of Botswana. In doing so, the study explored the potential value of place-based education in redressing concerns brought to light in postcolonial critiques of education in southern Africa. The study found that teachers sought to integrate environmental education into the curriculum through lessons that included references to local place names and local flora and fauna, lessons addressing issues related to environmental resource management in the region, and the acknowledgment and celebration of traditional lifestyle activities in the schools. The study also found that efforts to integrate environmental education into the curriculum were limited by a lack of educational resources needed to support these endeavors as well as a lack of adequate teacher training promoting this educational goal. The results also illustrate the potential value of place-based education in redressing the legacy of southern Africa’s colonial past in schools in Botswana and southern Africa.  相似文献   
136.
Here, I review research that has investigated the aetiology of injuries experienced by adolescent and adult fast bowlers. Mechanical factors play an important role in the aetiology of degenerative processes and injuries to the lumbar spine. This is particularly so in fast bowling, where a player must absorb vertical and horizontal components of the ground reaction force that are approximately five and two times body weight at front-foot and rear-foot impact, respectively. Attenuated forces are transmitted to the spine through the lower limb, while additional foces at the lumbo-sacral junction are caused by trunk hyperextension, lateral flexion and twisting during the delivery stride. Fast bowlers are classified as side-on, front-on or mixed. The mixed action is categorized by the lower body configuration of the front-on action and the upper body configuration of the side-on technique. This upper body configuration is produced by counter-rotation away from the batsman in the transverse plane about the longitudinal axis of the body of a line through the two shoulders. Counter-rotations of 12–40° during a delivery stride have predicted an increased incidence of lumbar spondylolysis, disc abnormality and muscle injury in fast bowlers. During the delivery stride, the mixed bowling action also shows: more lateral flexion and hyperextension of the lumbar spine at front-foot impact, and a greater range of motion of the trunk over the delivery stride when compared with the side-on and front-on techniques. The pars interarticularis of each vertebra is vulnerable to injury if repetitive flexion, rotation and hyperextension are present in the activity. Fast bowlers should reduce shoulder counter-rotation during the delivery stride to reduce the incidence of back injuries. When a player is required to bowl for extended periods irrespective of technique, overuse is also related to an increased incidence of back injuries and must be avoided.  相似文献   
137.
Purpose: The ability to anticipate the actions of opponents can be enhanced through perceptual-skill training, though there is doubt regarding the most effective form of doing so. We sought to evaluate whether perceptual-skill learning would be enhanced when supplemented with guiding visual information. Method: Twenty-eight participants without soccer-playing experience were assigned to a guided perceptual-training group (n = 9), an unguided perceptual-training group (n = 10), or a control group (n = 9). The guided perceptual-training group received half of their trials with color cueing that highlighted either the key kinematic changes in the kicker's action or the known visual search strategy of expert goalkeepers. The unguided perceptual-training group undertook an equal number of trials of practice, but all trials were without guidance. The control group undertook no training intervention. All participants completed an anticipation test immediately before and after the 7-day training intervention, as well as a 24-hr retention test. Results: The guided perceptual-training group significantly improved their response accuracy for anticipating the direction of soccer penalty kicks from preintervention to postintervention, whereas no change in performance was evident at posttest for either the unguided perceptual-training group or the control group. The superior performance of the guided perceptual-training group was preserved in the retention test and was confirmed when relative changes in response time were controlled using a covariate analysis. Conclusions: Perceptual training supplemented with guiding information provides a level of improvement in perceptual anticipatory skill that is not seen without guidance.  相似文献   
138.
Abstract

This study aimed to assess changes in bowling technique and lumbar load over the course of a bowling spell in adolescent fast bowlers, and to investigate the relationship between lumbar loads during fast bowling and kinematic factors which have previously been associated with low back injury. Three-dimensional motion analysis was carried out on forty participants who performed an 8-over bowling spell. There were no significant changes in bowling technique or lumbar loads over the course of the spell. Bowling with a more extended front knee, faster ball release speed and increased shoulder counter-rotation were related to increased lumbo-pelvic loading – in particular peak transverse plane rotation moments and anterior-posterior shear forces. These lumbar loads may be a factor in low back injury aetiology and future studies should investigate the relationship between lumbar loading, injury incidence and other risk factors.  相似文献   
139.
Abstract

The purpose of this study was to examine knee extensor/flexor muscle strength and physical activity in healthy males and females approaching retirement. Peak torques of the knee extensor and knee flexor muscle groups were measured bilaterally in 95 individuals (mean age 59.4 years) using an isokinetic dynamometer. Isokinetic concentric contractions were performed at angular velocities of 1.05 and 3.14 rad · s?1. Physical activity, including household, leisure, and sporting activities, was assessed. The results show that the average peak torques exhibited were lower than previously reported in studies using the same methodology with different populations of similar age and body size. Over one-third of the participants were sedentary, with just 13% being active enough to obtain health benefits. The poor muscle strength and low physical activity of this self selecting group of healthy working adults were surprising, and potentially a cause for concern. The combination of retirement being a potential watershed for a decrease in physical activity and the known age-related decline in physical performance indicates that some of these participants are at risk of losing their functional independence fairly early in the retirement stage. We recommend the introduction of effective health promotion interventions for individuals approaching retirement, encouraging them to become more physically active.  相似文献   
140.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号