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   15806篇
  免费   57篇
  国内免费   10篇
教育   12119篇
科学研究   1434篇
各国文化   43篇
体育   729篇
综合类   3篇
文化理论   431篇
信息传播   1114篇
  2022年   23篇
  2021年   43篇
  2020年   59篇
  2019年   114篇
  2018年   2288篇
  2017年   2201篇
  2016年   1690篇
  2015年   201篇
  2014年   227篇
  2013年   1002篇
  2012年   339篇
  2011年   806篇
  2010年   962篇
  2009年   550篇
  2008年   769篇
  2007年   1270篇
  2006年   173篇
  2005年   480篇
  2004年   534篇
  2003年   433篇
  2002年   220篇
  2001年   70篇
  2000年   126篇
  1999年   74篇
  1998年   74篇
  1997年   77篇
  1996年   73篇
  1995年   57篇
  1994年   67篇
  1993年   61篇
  1992年   44篇
  1991年   74篇
  1990年   51篇
  1989年   44篇
  1988年   36篇
  1987年   45篇
  1986年   44篇
  1985年   42篇
  1984年   47篇
  1983年   37篇
  1982年   31篇
  1981年   33篇
  1980年   29篇
  1979年   22篇
  1978年   29篇
  1977年   36篇
  1976年   28篇
  1975年   20篇
  1974年   22篇
  1971年   12篇
排序方式: 共有10000条查询结果,搜索用时 375 毫秒
61.
The turn to oral history in Qatar and the Arabian (also known as Persian) Gulf is not a rejection of traditional archival authority as has been the case in other parts of the world. In the Gulf, oral history has been embraced out of a desire to fill the silences of the largely unwritten record attributable to previous low levels of literacy and strong oral traditions in the region. Today, oral history is seen as the best method to capture details about traditional ways of life during the pre-oil era. After discussing archival concerns about the evidentiary nature of oral histories, this paper explores how it has come to be a crucial documentation tool in the Gulf, adapted to the specific nation building and cultural heritage priorities of the region.  相似文献   
62.
The purpose of this study is to find a theoretically grounded, practically applicable and useful granularity level of an algorithmically constructed publication-level classification of research publications (ACPLC). The level addressed is the level of research topics. The methodology we propose uses synthesis papers and their reference articles to construct a baseline classification. A dataset of about 31 million publications, and their mutual citations relations, is used to obtain several ACPLCs of different granularity. Each ACPLC is compared to the baseline classification and the best performing ACPLC is identified. The results of two case studies show that the topics of the cases are closely associated with different classes of the identified ACPLC, and that these classes tend to treat only one topic. Further, the class size variation is moderate, and only a small proportion of the publications belong to very small classes. For these reasons, we conclude that the proposed methodology is suitable to determine the topic granularity level of an ACPLC and that the ACPLC identified by this methodology is useful for bibliometric analyses.  相似文献   
63.
Many studies demonstrate differences in the coverage of citing publications in Google Scholar (GS) and Web of Science (WoS). Here, we examine to what extent citation data from the two databases reflect the scholarly impact of women and men differently. Our conjecture is that WoS carries an indirect gender bias in its selection criteria for citation sources that GS avoids due to criteria that are more inclusive. Using a sample of 1250 U.S. researchers in Sociology, Political Science, Economics, Cardiology and Chemistry, we examine gender differences in the average citation coverage of the two databases. We also calculate database-specific h-indices for all authors in the sample. In repeated simulations of hiring scenarios, we use these indices to examine whether women's appointment rates increase if hiring decisions rely on data from GS in lieu of WoS. We find no systematic gender differences in the citation coverage of the two databases. Further, our results indicate marginal to non-existing effects of database selection on women's success-rates in the simulations. In line with the existing literature, we find the citation coverage in WoS to be largest in Cardiology and Chemistry and smallest in Political Science and Sociology. The concordance between author-based h-indices measured by GS and WoS is largest for Chemistry followed by Cardiology, Political Science, Sociology and Economics.  相似文献   
64.
The present study aimed to investigate pre-sleep behaviours (including evening electronic device use) and sleep quantity in well-trained athletes. Seventy well-trained athletes (44 females, 26 males) aged 21 ± 4 y from a range of team and individual sports were asked to complete an online sleep diary for 7 days. The sleep diary included questions about pre-sleep behaviours (e.g. napping, caffeine intake), electronic device use in the 2 h prior to bedtime (e.g. type of device and duration of use) and sleep (e.g. time in bed, sleep onset latency). On average, athletes spent 8:20 ± 1:21 h in bed each night. Associations between age, time in bed and sleepiness suggested that younger athletes spent more time in bed (= -0.05, p = 0.001) but felt sleepier (r = -0.32, p < 0.01) than older athletes. On average, athletes mostly used electronic devices for 0–30 min prior to sleep. The use of multiple devices in the evening was associated with more perceived difficulty in falling asleep (= 0.22, p = 0.03), but no associations existed with other sleep variables. In summary, younger athletes may require later start times or improved sleep quality to resolve excessive sleepiness.  相似文献   
65.
66.
67.
68.
69.
70.
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