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   19181篇
  免费   274篇
  国内免费   123篇
教育   13359篇
科学研究   2294篇
各国文化   182篇
体育   1665篇
综合类   12篇
文化理论   156篇
信息传播   1910篇
  2021年   147篇
  2020年   272篇
  2019年   420篇
  2018年   556篇
  2017年   518篇
  2016年   511篇
  2015年   329篇
  2014年   437篇
  2013年   3491篇
  2012年   408篇
  2011年   431篇
  2010年   321篇
  2009年   336篇
  2008年   364篇
  2007年   391篇
  2006年   368篇
  2005年   363篇
  2004年   343篇
  2003年   322篇
  2002年   308篇
  2001年   304篇
  2000年   330篇
  1999年   333篇
  1998年   182篇
  1997年   191篇
  1996年   240篇
  1995年   217篇
  1994年   179篇
  1993年   172篇
  1992年   266篇
  1991年   259篇
  1990年   273篇
  1989年   289篇
  1988年   239篇
  1987年   249篇
  1986年   244篇
  1985年   272篇
  1984年   243篇
  1983年   226篇
  1982年   200篇
  1981年   194篇
  1980年   185篇
  1979年   262篇
  1978年   210篇
  1977年   192篇
  1976年   167篇
  1975年   146篇
  1974年   170篇
  1973年   148篇
  1971年   130篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
83.
84.
Twelve Chinese academic journals, indexed by SCI and financed by the National Natural Science Foundation (NNSF), were analysed using the 2000–2003 Total Citations and Impact Factor data from JCR. It is concluded that the quality of Chinese journals is generally low and has remained so despite recent government measures aimed at improvement. Several factors are influential – particularly the Chinese government's policy of encouraging submission to foreign journals. Finance, management, and the academic degree policy are also obstacles. It is suggested that the Chinese government should reconsider its current policies so as to encourage higher quality in domestic periodicals and thus a greater recognition of Chinese journals by the international academic community.  相似文献   
85.
This study sought to determine if exposure to two communication-oriented activities, videotapes and public service announcements, accounts for changes in substance use among adolescents participating in the Drug Resistance Strategies Project's keepin' it REAL adolescent substance use prevention curriculum. Middle-school students (4,734, 72% Latino) responded to questionnaires related to these analyses. An analysis of covariance (ANCOVA) model was fit separately to six substance use outcomes. The results suggested that intervention students who saw four or five videos engaged in less substance use in the past month than did students who saw fewer videos. Having seen the PSAs one or more times did not predict the reported change in substance use.  相似文献   
86.
The University of Colorado at Boulder Libraries used participatory management to reduce a special collections backlog. Without an increase in budget or staffing, technical and public services departments designed a pilot project to redeploy internal human resources in a collaborative manner. The process of backlog management is discussed.  相似文献   
87.
88.
89.
PURPOSE: This study describes the system architecture and user acceptance of a suite of programs that deliver information about newly updated library resources to clinicians' personal digital assistants (PDAs). DESCRIPTION: Participants received headlines delivered to their PDAs alerting them to new books, National Guideline Clearinghouse guidelines, Cochrane Reviews, and National Institutes of Health (NIH) Clinical Alerts, as well as updated content in UpToDate, Harrison's Online, Scientific American Medicine, and Clinical Evidence. Participants could request additional information for any of the headlines, and the information was delivered via e-mail during their next synchronization. Participants completed a survey at the conclusion of the study to gauge their opinions about the service. RESULTS/OUTCOME: Of the 816 headlines delivered to the 16 study participants' PDAs during the project, Scientific American Medicine generated the highest proportion of headline requests at 35%. Most users of the PDA Alerts software reported that they learned about new medical developments sooner than they otherwise would have, and half reported that they learned about developments that they would not have heard about at all. While some users liked the PDA platform for receiving headlines, it seemed that a Web database that allowed tailored searches and alerts could be configured to satisfy both PDA-oriented and e-mail-oriented users.  相似文献   
90.
OBJECTIVES: This paper explores the potential of multinomial logistic regression analysis to perform Web usage mining for an academic health sciences library Website. METHODS: Usage of database-driven resource gateway pages was logged for a six-month period, including information about users' network addresses, referring uniform resource locators (URLs), and types of resource accessed. RESULTS: It was found that referring URL did vary significantly by two factors: whether a user was on-campus and what type of resource was accessed. CONCLUSIONS: Although the data available for analysis are limited by the nature of the Web and concerns for privacy, this method demonstrates the potential for gaining insight into Web usage that supplements Web log analysis. It can be used to improve the design of static and dynamic Websites today and could be used in the design of more advanced Web systems in the future.  相似文献   
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