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   26252篇
  免费   201篇
  国内免费   8篇
教育   19580篇
科学研究   2472篇
各国文化   85篇
体育   1478篇
综合类   7篇
文化理论   470篇
信息传播   2369篇
  2021年   112篇
  2020年   166篇
  2019年   274篇
  2018年   2535篇
  2017年   2501篇
  2016年   1947篇
  2015年   346篇
  2014年   411篇
  2013年   2747篇
  2012年   545篇
  2011年   1131篇
  2010年   1096篇
  2009年   662篇
  2008年   995篇
  2007年   1416篇
  2006年   371篇
  2005年   601篇
  2004年   656篇
  2003年   549篇
  2002年   355篇
  2001年   330篇
  2000年   318篇
  1999年   268篇
  1998年   139篇
  1997年   178篇
  1996年   176篇
  1995年   181篇
  1994年   146篇
  1993年   165篇
  1992年   238篇
  1991年   218篇
  1990年   211篇
  1989年   246篇
  1988年   249篇
  1987年   210篇
  1986年   210篇
  1985年   220篇
  1984年   193篇
  1983年   233篇
  1982年   172篇
  1981年   161篇
  1980年   158篇
  1979年   234篇
  1978年   186篇
  1977年   172篇
  1976年   156篇
  1975年   130篇
  1974年   122篇
  1973年   128篇
  1971年   108篇
排序方式: 共有10000条查询结果,搜索用时 14 毫秒
51.
52.
From the Editor     
Educational Assessment, Evaluation and Accountability -  相似文献   
53.
54.
55.
56.
Working Graphs     
  相似文献   
57.
58.
59.
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   
60.
Efforts to represent knowledge effectively have been central to progress in various aspects of medical informatics. These efforts range from relatively simple "electronic textbooks" to fairly sophisticated knowledge-based systems, which function as well as, or even better than, human experts faced with similar problems. Knowledge bases have been developed in many fields, but the relatively limited domains and structured language of medicine, as well as the importance of information in the provision of good medical care, have made research in medical knowledge representation an area of intense activity. This paper reviews representative knowledge bases and knowledge-based systems in medicine: electronic textbooks such as PDQ and the Hepatitis Knowledge Base (HKB), rule-based systems such as MYCIN, causal models (e.g., CASNET), and hypothesis- or frame-based systems, exemplified by PIP and INTERNIST-1. The paper describes the relationships among divergent approaches and provides a sense of current and future trends. It examines problems in knowledge-based systems, particularly in knowledge representation and acquisition, and the responses to these challenges. The latter include the use of domain-independent software shells for constructing knowledge bases, the adaptation and use of previously existing knowledge bases, and multiple uses of the same knowledge base for different purposes.  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