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   11282篇
  免费   196篇
  国内免费   54篇
教育   7775篇
科学研究   1047篇
各国文化   176篇
体育   871篇
综合类   159篇
文化理论   137篇
信息传播   1367篇
  2022年   76篇
  2021年   151篇
  2020年   206篇
  2019年   254篇
  2018年   333篇
  2017年   379篇
  2016年   337篇
  2015年   312篇
  2014年   355篇
  2013年   2035篇
  2012年   400篇
  2011年   433篇
  2010年   408篇
  2009年   405篇
  2008年   493篇
  2007年   444篇
  2006年   406篇
  2005年   354篇
  2004年   239篇
  2003年   268篇
  2002年   245篇
  2001年   218篇
  2000年   173篇
  1999年   149篇
  1998年   142篇
  1997年   141篇
  1996年   139篇
  1995年   142篇
  1994年   126篇
  1993年   101篇
  1992年   119篇
  1991年   112篇
  1990年   105篇
  1989年   104篇
  1988年   88篇
  1987年   74篇
  1986年   66篇
  1985年   79篇
  1984年   61篇
  1983年   78篇
  1982年   75篇
  1981年   78篇
  1980年   83篇
  1979年   76篇
  1978年   54篇
  1977年   44篇
  1976年   52篇
  1975年   43篇
  1974年   40篇
  1971年   29篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
ABSTRACT

The aims of this study were to identify profiles of sedentary behaviour (SB) patterns, based on leisure-time self-reported SB modalities (screen, educative, social, and relaxing) and to evaluate changes in these profiles over 2 years among Spanish youth aged 8–18 years. Latent profile analysis (LPA), a data-driven analytic approach, was used to identify groups of boys and girls (n = 1553; 48% girls; mean±SD age: 12.56 ± 2.49 y) with distinct SB profiles using the SB modalities (time/d) as input variables. Latent transition analysis, an extension of LPA that uses longitudinal data, was used to analyse 2-year changes in these profiles. At baseline, four and three SB profiles were found among boys (labelled: screen, educative, social, and relaxing) and girls (labelled: screen/social, educative, and relaxing), respectively. Overall, more girls (range: 48%-67%) had the same profile over time, than boys (40%-52%). Participants with a screen or relaxing SB profile at baseline were more likely to have an educative profile after 2 years. Youth with a social and an educative SB profile at baseline were more likely to transition to profiles characterized by higher screen and social SB, respectively. Using a novel and person-centered approach, this study identified gender-specific SB profiles that were moderately stable over time.  相似文献   
2.
3.
4.
ABSTRACT

To better understand doping-related attitude change, it is important to consider not only the amount of thinking (i.e., elaboration) done by message recipients, but also the favourability of their thoughts in response to the proposal, as well as the perceived validity in their thoughts. The main goal of the present study was to analyse the effects of a meta-cognitive process (i.e., thought validation) on attitudes related to doping. Thus, we randomly assigned participants to read a message either against or in favour of legalising several doping behaviours. Participants listed their thoughts regarding the proposal and indicated the perceived validity in their thoughts, then reported their attitudes. As hypothesised, the message against legalisation elicited more unfavourable thoughts and attitudes than the message in favour of legalisation. Most relevantly, the effects of the message direction on attitudes were greater for participants with higher (vs. lower) levels of thought validity. Furthermore, consistent with the thought validation process, results revealed that thought favourability was a better predictor of attitudes for participants with higher (vs. lower) perceived thought validity, indicating that perceiving one’s thoughts as valid plays an important role in persuasion. These findings provide novel insights for research and interventions regarding doping in sports.  相似文献   
5.
游泳运动员专项始训年龄段运动素质的生理特点分析   总被引:3,自引:0,他引:3  
本文通过文献资料法、常规数理统计法及调查访问法 ,对我国部分优秀游泳运动员各训练阶段的年龄参数进行调查研究 ,并从运动生理学角度对专项始训年龄段的运动员运动素质的生理特点进行分析 ,发现 12 - 14岁是年龄组运动员开始专项训练的适宜年龄段 ,运动员的运动素质在此年龄段已有一定的发展 ,有的还处在发展敏感期 ,能达到专项训练的要求。  相似文献   
6.
泛太平洋地区冰壶锦标赛评析   总被引:13,自引:11,他引:2  
通过对泛太平洋地区冰壶锦标赛的评析,客观评价中国冰壶在泛太平洋地区目前所处的地位及冰壶运动在中国发展的潜力。客观地分析了我们训练中所存在的问题与差距,并为中国冰壶运动的发展提出了积极的建议和意见。  相似文献   
7.
8.
Measuring Search Engine Quality   总被引:12,自引:3,他引:9  
The effectiveness of twenty public search engines is evaluated using TREC-inspired methods and a set of 54 queries taken from real Web search logs. The World Wide Web is taken as the test collection and a combination of crawler and text retrieval system is evaluated. The engines are compared on a range of measures derivable from binary relevance judgments of the first seven live results returned. Statistical testing reveals a significant difference between engines and high intercorrelations between measures. Surprisingly, given the dynamic nature of the Web and the time elapsed, there is also a high correlation between results of this study and a previous study by Gordon and Pathak. For nearly all engines, there is a gradual decline in precision at increasing cutoff after some initial fluctuation. Performance of the engines as a group is found to be inferior to the group of participants in the TREC-8 Large Web task, although the best engines approach the median of those systems. Shortcomings of current Web search evaluation methodology are identified and recommendations are made for future improvements. In particular, the present study and its predecessors deal with queries which are assumed to derive from a need to find a selection of documents relevant to a topic. By contrast, real Web search reflects a range of other information need types which require different judging and different measures.  相似文献   
9.
This paper addresses the need to recognize the importance, and the challenges, of preserving the hugely expanding record of medicine today for historians of the future. We are faced not only with an increase in traditional publishing formats, but also with the rapid growth in electronic communications. Two celebrated medical cases, one from the late seventeenth century and one from the late twentieth, are used to illustrate the differences and the difficulties. The need for active and effective professional collaboration is stressed; libraries should work together to address these issues.  相似文献   
10.
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