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   2321篇
  免费   18篇
  国内免费   2篇
教育   1326篇
科学研究   625篇
各国文化   29篇
体育   185篇
文化理论   27篇
信息传播   149篇
  2020年   30篇
  2019年   49篇
  2018年   75篇
  2017年   56篇
  2016年   64篇
  2015年   38篇
  2014年   41篇
  2013年   480篇
  2012年   54篇
  2011年   38篇
  2010年   33篇
  2009年   34篇
  2008年   49篇
  2007年   46篇
  2006年   37篇
  2005年   44篇
  2004年   50篇
  2003年   23篇
  2002年   28篇
  2001年   26篇
  2000年   27篇
  1999年   13篇
  1997年   15篇
  1996年   25篇
  1995年   24篇
  1994年   27篇
  1993年   28篇
  1992年   19篇
  1991年   14篇
  1990年   24篇
  1989年   16篇
  1987年   20篇
  1986年   19篇
  1985年   18篇
  1983年   19篇
  1982年   16篇
  1981年   15篇
  1978年   21篇
  1930年   20篇
  1929年   28篇
  1928年   33篇
  1927年   32篇
  1926年   30篇
  1925年   52篇
  1924年   33篇
  1923年   34篇
  1921年   15篇
  1920年   28篇
  1919年   13篇
  1868年   15篇
排序方式: 共有2341条查询结果,搜索用时 15 毫秒
71.
72.
Interest in the quality of published research is evident across the range of disciplines including education. Several comprehensive studies either sponsored or published by the American Educational Research Association attest to this fact. In the sciences, citation analysis is attracting interest as a methodology for assessing research. The procedure has both theoretical and practical promise. The present study considers an overlooked source of information, reprint requesting, as a possible adjunct to citation analysis. The study stems from the questionnaire responses of 24 reprint requestors for an article by the authors. Requestor characteristics, motives, and reprint uses are considered. Implications for further research are advanced.  相似文献   
73.
The aims of this study were to examine and compare selected physiological and metabolic responses of wheelchair athletes in two paraplegic racing classes [T3: n = 8 (lesion levels T1-T7; paraplegics); T4: n = 9 (lesion levels below T7; paraplegics)] to prolonged exercise. In addition, we describe the responses of three tetraplegic athletes [T2: n = 3 (lesion levels C6/C7: tetraplegics)]. Twenty athletes completed 90 min of exercise at 75% VO2peak on a motorized treadmill adapted for wheelchairs. The mean (+/- s) heart rates of the T3 and T4 racing classes were 165 +/- 2 and 172 +/- 6 beats.min-1, respectively. For the T4 racing class, heart rate gradually increased during the test (P < 0.05), whereas for the T3 racing class, heart rate reached a plateau after an initial increase. The mean heart rate of the tetraplegics was 114 +/- 3 beats.min-1. The T3 and T4 classes exhibited similar respiratory exchange ratios, plasma lactate and glucose concentrations throughout the test. For both the T3 and T4 racing class, free fatty acid, glycerol, ammonia, urea and potassium concentrations had increased from resting values by the end of the test (P < 0.05). In conclusion, the results of this study suggest that endurance-trained wheelchair athletes are able to maintain velocities equivalent to the same relative exercise intensity (75% VO2peak) for prolonged periods irrespective of lesion level.  相似文献   
74.
The purpose of this study was to further understand the biomechanical differences between the standing and crouch starting methods, and to investigate whether one of the starting styles provides better acceleration and proves to be faster. Six university track team sprinters performed 2 x 3 x 50 m trials. Digitised video, photocell timing, and velocity data revealed that during the first steps of the performance the standing start produced higher body centre of mass horizontal velocity than the crouch start. This may be due to the longer distance between the feet in the standing start, which caused longer push-off phases, and the work against gravity in the crouch start. However, this advantage in horizontal velocity disappeared by the 10 m mark, where similar velocities were recorded with both start styles. Further, there was no statistically significant difference between the two starting styles in horizontal velocity at the 25 m mark, nor in the time to reach the 25 m or 50 m mark. Regarding relay running, where athletes need to decide to adopt either a crouch start without starting blocks or a standing start, there seems to be no specific reason for outgoing athletes to use a crouch start, although this area warrants further investigation.  相似文献   
75.
76.
77.
78.
79.
80.
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