全文获取类型
收费全文 | 1295篇 |
免费 | 24篇 |
国内免费 | 4篇 |
专业分类
教育 | 902篇 |
科学研究 | 81篇 |
各国文化 | 17篇 |
体育 | 136篇 |
文化理论 | 23篇 |
信息传播 | 164篇 |
出版年
2022年 | 16篇 |
2021年 | 19篇 |
2020年 | 27篇 |
2019年 | 46篇 |
2018年 | 61篇 |
2017年 | 63篇 |
2016年 | 57篇 |
2015年 | 34篇 |
2014年 | 45篇 |
2013年 | 248篇 |
2012年 | 43篇 |
2011年 | 44篇 |
2010年 | 45篇 |
2009年 | 36篇 |
2008年 | 39篇 |
2007年 | 57篇 |
2006年 | 37篇 |
2005年 | 37篇 |
2004年 | 35篇 |
2003年 | 34篇 |
2002年 | 25篇 |
2001年 | 22篇 |
2000年 | 12篇 |
1999年 | 11篇 |
1998年 | 16篇 |
1997年 | 11篇 |
1996年 | 13篇 |
1995年 | 7篇 |
1994年 | 10篇 |
1992年 | 5篇 |
1991年 | 13篇 |
1989年 | 8篇 |
1988年 | 7篇 |
1987年 | 13篇 |
1986年 | 5篇 |
1985年 | 8篇 |
1984年 | 6篇 |
1983年 | 10篇 |
1982年 | 6篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1978年 | 8篇 |
1977年 | 4篇 |
1976年 | 7篇 |
1975年 | 6篇 |
1973年 | 6篇 |
1972年 | 4篇 |
1971年 | 5篇 |
1970年 | 4篇 |
1966年 | 4篇 |
排序方式: 共有1323条查询结果,搜索用时 15 毫秒
41.
The 100 ms ruling for false start disqualification at athletic competitions governed by the International Association of Athletics Federations has been in force since the early 1990s. Throughout this period, there have been marked changes to the rules that govern the disqualification of athletes from sprint events incorporating starts from blocks. This study analysed all available World and European Championship response-time (RT) data from 1999 to 2014 to examine effects of rule changes on competition RT at major championships. The exponentially modified Gaussian distribution was used to model RT and make comparisons relative to athletes’ sex, ruling periods and competition rounds. Revised RT thresholds of 115 ms and 119 ms were identified for men and women, respectively, indicating that the current 100 ms rule could result in some false starts not being detected in competitive athletics. The study proposes that when using existing International Association of Athletics Federations approved systems, the false start detection threshold should be increased and that men and women athletes should have different thresholds because of substantial evidence of a sex-based difference in RT in elite-standard athletes. 相似文献
42.
Ashley G. B. Willmott Mark Hayes Kirsty A. M. Waldock Rebecca L. Relf Emily R. Watkins Carl A. James 《Journal of sports sciences》2017,35(22):2249-2256
Multistage, ultra-endurance events in hot, humid conditions necessitate thermal adaptation, often achieved through short term heat acclimation (STHA), to improve performance by reducing thermoregulatory strain and perceptions of heat stress. This study investigated the physiological, perceptual and immunological responses to STHA prior to the Marathon des Sables. Eight athletes (age 42 ± 4 years and body mass 81.9 ± 15.0 kg) completed 4 days of controlled hyperthermia STHA (60 min·day?1, 45°C and 30% relative humidity). Pre, during and post sessions, physiological and perceptual measures were recorded. Immunological measures were recorded pre-post sessions 1 and 4. STHA improved thermal comfort (P = 0.02), sensation (P = 0.03) and perceived exertion (P = 0.04). A dissociated relationship between perceptual fatigue and Tre was evident after STHA, with reductions in perceived Physical (P = 0.04) and General (P = 0.04) fatigue. Exercising Tre and HR did not change (P > 0.05) however, sweat rate increased 14% (P = 0.02). No changes were found in white blood cell counts or content (P > 0.05). Four days of STHA facilitates effective perceptual adaptations, without compromising immune status prior to an ultra-endurance race in heat stress. A greater physiological strain is required to confer optimal physiological adaptations. 相似文献
43.
Eric Ma 《Inter-Asia Cultural Studies》2013,14(2):187-200
The paper attempts to work out the link between the structuring of the public domain and hegemonic masculinities in contemporary Kerala, South India. Using the debates around an incident of sexual harassment that happened in 1999, it argues for a conjunctural understanding of the contemporary where various events and moments in history are replayed through narrativization and popular memory. The paper goes on to analyse the debates around the incident that produce a ‘narrative public domain’, to foreground the various notions of masculinity that construct and structure it in relation to notions of female sexuality and changing structures of family. These notions of masculinity could be, the paper argues, a starting point for a historical inquiry into Kerala's modernity – an inquiry that would throw light on the past and the ways in which the contemporary is produced through its historical legacies. 相似文献
44.
Understanding the role of shaft stiffness in the golf swing 总被引:3,自引:3,他引:0
Theoretically, shaft stiffness can alter shot distance by increasing clubhead speed or altering clubhead orientation at impact.
A 3D forward dynamics model of a golfer and flexible club simulated the downswing. A genetic algorithm optimized the coordination
of the model’s muscles (four torque generators) to maximize clubhead speed. The maximum torque output and maximum rate of
torque development from the torque generators were varied to simulate the swing of golfers that generate different clubhead
speeds. Four shafts of varying stiffness (flexible, regular, stiff, and completely rigid) were entered into these simulations
to examine the role that shaft flexibility had on clubhead speed and orientation at impact. Shaft stiffness was found to have
a meaningful effect only on clubhead orientation (dynamic loft and dynamic close) at impact. There was no evidence to support
the premise that matching the stiffness properties of the shaft with the golfer would improve clubhead speed. 相似文献
45.
46.
47.
48.
49.
50.
Describing the plastic deformation of aluminium softball bats 总被引:1,自引:1,他引:0
Hollow aluminium bats were introduced over 30 years ago to provide improved durability over wooden bats. Since their introduction,
however, interest in hollow bats has focused almost exclusively around their hitting performance. The aim of this study was
to take advantage of the progress that has been made in predicting bat performance using finite elements and apply it to describe
bat durability. Accordingly, the plastic deformation from a ball impact of a single-wall aluminum bat was numerically modelled.
The bat deformation from the finite-element analysis was then compared with experiment using a high-speed bat test machine.
The ball was modelled as an isotropic, homogeneous, viscoelastic sphere. The viscoelastic parameters of the ball model were
found from instrumented, high-speed, rigid-wall ball impacts. The rigid-wall ball impacts were modelled numerically and showed
good agreement with the experimentally obtained response. The strain response of the combined bat-ball model was verified
with a strain-gauged bat at intermediate ball impact speeds in the elastic range. The strain response of the bat-ball model
exhibited positive correlation with the experimental measurements. High-speed bat-ball impacts were performed experimentally
and simulated numerically at increasing impact speeds which induced correspondingly increased dent sizes in the bat. The plastic
deformation from the numerical model found good agreement with experiment provided the aluminium work hardening and strain
rate effects were appropriately described. The inclusion of strain rate effects was shown to have a significant effect on
the bat deformations produced in the finite-element simulations. They also helped explain the existence of high bat stresses
found in many performance models. 相似文献