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   34649篇
  免费   325篇
  国内免费   139篇
教育   24790篇
科学研究   4154篇
各国文化   180篇
体育   2220篇
综合类   18篇
文化理论   547篇
信息传播   3204篇
  2021年   224篇
  2020年   355篇
  2019年   503篇
  2018年   2756篇
  2017年   2613篇
  2016年   2146篇
  2015年   510篇
  2014年   703篇
  2013年   4117篇
  2012年   718篇
  2011年   1222篇
  2010年   1237篇
  2009年   842篇
  2008年   1088篇
  2007年   1546篇
  2006年   513篇
  2005年   814篇
  2004年   835篇
  2003年   718篇
  2002年   486篇
  2001年   430篇
  2000年   453篇
  1999年   440篇
  1998年   221篇
  1997年   262篇
  1996年   275篇
  1995年   245篇
  1994年   225篇
  1993年   210篇
  1992年   370篇
  1991年   346篇
  1990年   336篇
  1989年   379篇
  1988年   316篇
  1987年   319篇
  1986年   311篇
  1985年   362篇
  1984年   302篇
  1983年   304篇
  1982年   238篇
  1981年   235篇
  1980年   216篇
  1979年   337篇
  1978年   252篇
  1977年   241篇
  1976年   191篇
  1975年   179篇
  1974年   207篇
  1973年   190篇
  1971年   160篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
83.
84.
Acquiring both published and unpublished documents produced in Africa is, generally, a difficult task due to the existing poor state of bibliographic control and the publishing industry. It is even more difficult to obtain unpublished documents in a specialized area of study such as demography--a diffuse area which cuts across several disciplines. This paper discusses the problems encountered on acquisition trips to some African countries to acquire unpublished population material. To help solve the problems, the Population Association of Africa must persuade its members to send copies of their publications to population libraries and documentation centers in their individual countries for dissemination to the other users in Africa. The various organizations and institutions in Africa engaged in the teaching and research of population studies should have an agreement to exchange copies of their theses. The Economic Commission for Africa (ECA) and the Organization of African Unity (OAU) should make representations to the various African member countries on the need to disseminate the results of vital censuses and surveys conducted. Finally, the Population Information Network for Africa (POPIN-AFRICA) with its coordinating unit at the population division of ECA should ensure that all the nodes of the network have the financial and other resources to be able to acquire the relevant documents needed for their operations.  相似文献   
85.
Computers are integral to medical practice, education, and research. While medical students learn computer skills during their training, many practicing physicians do not have the same computer experience. To familiarize this group with the exciting developments in medical informatics, the Himmelfarb Health Sciences Library and Department of Computer Medicine at the George Washington University Medical Center organized a workshop "Introducing Your Office Computer!" for attending physicians. The workshop featured a short lecture/video presentation on computer applications in medicine followed by a "computer fair" of five computer applications. Eleven physicians attended the workshop. Feedback was very positive; many called later to request more detailed instructions on using the programs demonstrated. It was a valuable experience for the staff, and new bridges were built between departments and clients.  相似文献   
86.
The Alfred Taubman Medical Library at the University of Michigan has offered instruction in online literature searching to third-year pharmacy students as a component of the course "Drug Information and Scientific Literature Evaluation" since 1983. In the spring of 1989, a follow-up study was conducted to assess the impact of instruction on four classes of graduates. Of a pool of 151 graduates, 90 (60%) responded to a mailed questionnaire on their use of information and computerized literature searching. The respondents were divided into four subgroups: end-user searchers, users of intermediaries, end users who used intermediaries, and those who did not use computerized literature search systems. Seventy-two percent of the respondents used some type of computerized literature searching, and 42% performed their own searches. The four subgroups differed in general computer use, familiarity with MEDLINE search terminology, information use, reasons for using or not using literature searching, and characteristics of searches (i.e., type, time frame, amount, and frequency). Training in end-user search systems appears to have had an impact on the continued use of computerized literature searching several years after the formal educational program.  相似文献   
87.
88.
89.
90.
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