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   25494篇
  免费   185篇
  国内免费   8篇
教育   18929篇
科学研究   2466篇
各国文化   82篇
体育   1460篇
综合类   7篇
文化理论   471篇
信息传播   2272篇
  2021年   107篇
  2020年   155篇
  2019年   267篇
  2018年   2525篇
  2017年   2487篇
  2016年   1933篇
  2015年   337篇
  2014年   398篇
  2013年   2668篇
  2012年   532篇
  2011年   1118篇
  2010年   1097篇
  2009年   651篇
  2008年   982篇
  2007年   1411篇
  2006年   365篇
  2005年   586篇
  2004年   649篇
  2003年   541篇
  2002年   347篇
  2001年   323篇
  2000年   310篇
  1999年   262篇
  1998年   133篇
  1997年   174篇
  1996年   169篇
  1995年   166篇
  1994年   133篇
  1993年   150篇
  1992年   222篇
  1991年   204篇
  1990年   202篇
  1989年   236篇
  1988年   223篇
  1987年   195篇
  1986年   190篇
  1985年   205篇
  1984年   179篇
  1983年   211篇
  1982年   144篇
  1981年   142篇
  1980年   133篇
  1979年   211篇
  1978年   162篇
  1977年   154篇
  1976年   132篇
  1975年   120篇
  1974年   110篇
  1973年   120篇
  1971年   95篇
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
41.
Cerebral activity, as reflected by power in the alpha waveband (8-13 Hz), was examined prior to the performance of three tasks with different effort and accuracy requirements. The study aimed to further investigate changes in activity observed in an earlier study in which expert karate performers exhibited significant increases in alpha band power during preparation for a training task. In contrast to the earlier research, the high effort task produced a significant decrease in 'alpha' power prior to performance. 'Alpha' power prior to the high accuracy task showed significant differences mediated by the outcome. Successful performance was preceded by higher levels of 'alpha' power than unsuccessful attempts. The reported use of a cognitive strategy on the first task produced a significant difference in activity, lower alpha power being associated with the use of such a technique.  相似文献   
42.
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   
43.
Data from the International Social Survey Program indicate considerablevariation in the desire of respondents for increased spendingon the environment in Australia, Austria, Great Britain, theUnited States, and West Germany. This paper explores this variationwith the following objectives: (1) to determine the extent towhich the social bases of environmental concern are consistentacross nations; (2) to determine how the issue of the environmenthas been politicized in the five industrialized nations, focusingon the association of Old Leftist concerns and environmentalconcern; and (3) to determine the extent to which the socialbases of environmental concern can explain the cross-nationalvariation. The study usesa regression analysis, testing variablesrepresenting the social bases of environmental concern frompast research in the United States, a scale representing commitmentto the platform of the Old Left, and dummy variables for eachcountry. The results show that the social bases of environmentalconcern are the same in the five countries studied, includinga consistent positive association of Old Leftism with environmentalconcern. However, substantial variation between countries inthe overall level of concern remains. Potential sources of theremaining variation are examined.  相似文献   
44.
45.
46.
47.
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   
48.
49.
Moral minds     
Steve Clarke 《Minerva》2008,46(1):147-150
  相似文献   
50.
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