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   25524篇
  免费   443篇
  国内免费   36篇
教育   18514篇
科学研究   2163篇
各国文化   278篇
体育   1950篇
综合类   35篇
文化理论   244篇
信息传播   2819篇
  2022年   129篇
  2021年   251篇
  2020年   404篇
  2019年   568篇
  2018年   783篇
  2017年   879篇
  2016年   799篇
  2015年   506篇
  2014年   661篇
  2013年   5176篇
  2012年   622篇
  2011年   713篇
  2010年   548篇
  2009年   542篇
  2008年   614篇
  2007年   584篇
  2006年   531篇
  2005年   467篇
  2004年   440篇
  2003年   413篇
  2002年   448篇
  2001年   486篇
  2000年   460篇
  1999年   459篇
  1998年   262篇
  1997年   285篇
  1996年   312篇
  1995年   269篇
  1994年   256篇
  1993年   241篇
  1992年   321篇
  1991年   329篇
  1990年   354篇
  1989年   332篇
  1988年   305篇
  1987年   253篇
  1986年   274篇
  1985年   337篇
  1984年   262篇
  1983年   247篇
  1982年   193篇
  1981年   204篇
  1980年   171篇
  1979年   260篇
  1978年   204篇
  1977年   207篇
  1976年   170篇
  1975年   143篇
  1974年   136篇
  1973年   155篇
排序方式: 共有10000条查询结果,搜索用时 546 毫秒
121.
122.
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   
123.
124.
125.
126.
127.
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   
128.
129.
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   
130.
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   
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