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   19941篇
  免费   287篇
  国内免费   24篇
教育   13860篇
科学研究   2375篇
各国文化   195篇
体育   1558篇
综合类   8篇
文化理论   144篇
信息传播   2112篇
  2021年   196篇
  2020年   267篇
  2019年   391篇
  2018年   536篇
  2017年   493篇
  2016年   495篇
  2015年   329篇
  2014年   435篇
  2013年   3555篇
  2012年   416篇
  2011年   447篇
  2010年   388篇
  2009年   322篇
  2008年   383篇
  2007年   331篇
  2006年   341篇
  2005年   299篇
  2004年   342篇
  2003年   286篇
  2002年   256篇
  2001年   554篇
  2000年   393篇
  1999年   338篇
  1998年   183篇
  1997年   217篇
  1996年   206篇
  1995年   182篇
  1994年   192篇
  1993年   190篇
  1992年   278篇
  1991年   289篇
  1990年   285篇
  1989年   288篇
  1988年   244篇
  1987年   249篇
  1986年   257篇
  1985年   298篇
  1984年   237篇
  1983年   229篇
  1982年   211篇
  1981年   188篇
  1980年   181篇
  1979年   254篇
  1978年   211篇
  1977年   190篇
  1976年   156篇
  1975年   158篇
  1974年   161篇
  1973年   162篇
  1972年   132篇
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
71.
72.
73.
A user study of the Index Medicus done at the Walter Reed Army Medical Center included responses from a group of sixty researchers, clinicians, residents, and interns. An analysis of the questionnaire shows that, while all respondents use the Index Medicus, most use it to search for a specific subject or a specific author reference. Comments received were critical of the delay from the time of journal publication until the appearance of its citation in Index Medicus. Suggestions were offered concerning the type of publication most of the respondents would prefer.  相似文献   
74.
Since a sizeable hospital must have a library, it must have a library committee. Like all hospital committees, this one is to help maintain standards of medical care and to mediate between staff and administration. Unlike others, it clusters around one elected member (the chairman) and one employee (the librarian). A dynamic librarian can, and should, influence and inspire the committee's deliberations; and must be able to depend upon the support of the physician members of the committee.  相似文献   
75.
Cancelled charge slips collected over a one-year period supply the data for this analysis of circulation in the Yale Medical Library. Full-time teaching faculty are the heaviest users of journal literature, and students, of monograph literature. Faculties of Medical School departments are compared in terms of their use of material in individual subjects. Subject literatures are analyzed in terms of groups of users borrowing from them. The extent to which journal titles used by medical students are also used by Medical School faculty is examined. One of the products of the study is a rank list of journal titles used in the Library. Results are presented in several tables.  相似文献   
76.
The American Hospital Association (AHA) Resource Center indexes journals for the Health Planning and Administration (HEALTH) database and Hospital Literature Index (HLI). These journals, designated special list health journals, are selected to provide access to a wide and balanced coverage of hospital and health care administration and health policy literature. This article provides background information on HEALTH and HLI and describes special list health journals in detail (including historical information, information sources, and broad subject divisions). It also discusses AHA policies relating to journal and article selection and current subject distribution of special list health journals.  相似文献   
77.
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   
78.
Serials, one of the more complicated areas of library technical endeavors, has lacked the benefit of standards for a long time. Even now, with standards beginning to be available, the majority of institutions are not working within standard serials formats. A survey to determine the use of serials standards in libraries was conducted in 1988 by the American Library Association, Resources and Technical Services Division, Serials Section, Committee to Study Serials Standards. In the spring of 1988 a survey was sent to a group encompassing the Association of Research Libraries members, CONSER participants, United States Newspaper Program participants, Microform Project libraries, and some vendors and librarians who attended the Committee meetings on a regular basis. The survey questionnaire assessed the current level of serials standards awareness of librarians and vendors. Topics included the type of serials systems used, standards relevant to serials control and union listing and whether or not they are implemented, types and levels of training staff received in the application of standards, benefits of the standards, and areas where standards are most needed.  相似文献   
79.
80.
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