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   26561篇
  免费   446篇
  国内免费   42篇
教育   19151篇
科学研究   2346篇
各国文化   293篇
体育   2041篇
综合类   35篇
文化理论   235篇
信息传播   2948篇
  2022年   140篇
  2021年   259篇
  2020年   418篇
  2019年   592篇
  2018年   818篇
  2017年   889篇
  2016年   849篇
  2015年   510篇
  2014年   665篇
  2013年   5331篇
  2012年   641篇
  2011年   726篇
  2010年   568篇
  2009年   547篇
  2008年   619篇
  2007年   588篇
  2006年   514篇
  2005年   478篇
  2004年   447篇
  2003年   396篇
  2002年   451篇
  2001年   481篇
  2000年   450篇
  1999年   464篇
  1998年   245篇
  1997年   279篇
  1996年   298篇
  1995年   264篇
  1994年   260篇
  1993年   235篇
  1992年   348篇
  1991年   367篇
  1990年   379篇
  1989年   356篇
  1988年   326篇
  1987年   298篇
  1986年   300篇
  1985年   375篇
  1984年   314篇
  1983年   308篇
  1982年   239篇
  1981年   245篇
  1980年   207篇
  1979年   285篇
  1978年   264篇
  1977年   220篇
  1976年   167篇
  1975年   145篇
  1974年   127篇
  1973年   152篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
A cooperative acquisition program for monographs for the twelve resource libraries in Region IX of the Regional Medical Library Network is described. Each of the participating libraries has agreed to purchase all books of an assigned publisher which fall within a prescribed subject-format profile. It is hoped that this will help to reduce unnecessary duplication and contribute toward the development of resources in the region.  相似文献   
103.
104.
105.
106.
107.
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   
108.
Evaluators of library programs have different perspectives on why to conduct an evaluation and also how to do so. The author suggests that a minimal approach to conducting a library program evaluation is to prove that the program exists. But this perspective has expanded to include different degrees of interest in the client and operations, culminating in a combined focus that leads evaluators to conduct outcome assessments. The chapter includes speculation on what motivates managers to undertake an evaluation, a review of some ways that library evaluations are conducted, and a discussion of several examples of program evaluations. Though there are not single directives for undertaking a library program evaluation, there are a variety of tools and advice to entice librarians to do more of them as a way to improve understanding the value of a library to its clientele and in society.  相似文献   
109.
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   
110.
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