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   29094篇
  免费   260篇
  国内免费   65篇
教育   21660篇
科学研究   2431篇
各国文化   182篇
体育   1878篇
综合类   45篇
文化理论   475篇
信息传播   2748篇
  2022年   124篇
  2021年   216篇
  2020年   271篇
  2019年   411篇
  2018年   2656篇
  2017年   2584篇
  2016年   2064篇
  2015年   463篇
  2014年   611篇
  2013年   3584篇
  2012年   730篇
  2011年   1187篇
  2010年   1276篇
  2009年   850篇
  2008年   1061篇
  2007年   1528篇
  2006年   520篇
  2005年   779篇
  2004年   712篇
  2003年   610篇
  2002年   388篇
  2001年   402篇
  2000年   324篇
  1999年   267篇
  1998年   177篇
  1997年   182篇
  1996年   176篇
  1995年   148篇
  1994年   157篇
  1993年   143篇
  1992年   223篇
  1991年   222篇
  1990年   247篇
  1989年   220篇
  1988年   178篇
  1987年   186篇
  1986年   194篇
  1985年   179篇
  1984年   191篇
  1983年   170篇
  1982年   138篇
  1981年   141篇
  1980年   137篇
  1979年   198篇
  1978年   166篇
  1977年   117篇
  1976年   120篇
  1975年   122篇
  1973年   107篇
  1971年   118篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
This paper supplements information given in earlier papers on the UCLA MEDLARS Search Station. Four major machine problem areas in the operation of a decentralized station are identified: adjustments required to run a large information retrieval type program in an academic computing facility serving many users; handicap in running time for COBOL programs; advent of the third generation of computers with attendant preparation; and need for constant current communication among all members of a decentralized network system. Statistics are given for the initial operating period, January-May 1966: 119 search requests received, 109 formulated, and 60 fully processed. Parallel searches with other MEDLARS installations, comparisons of MEDLARS and manual Index Medicus searches, and other search activities are reported.  相似文献   
73.
Adequate research in the peripheral field of medical geography requires familiarity with the literature of medicine, geography, and other environmentally oriented fields. The pertinent literature of the two primary disciplines, as well as that of anthropology, nutrition, and human bioclimatology, is surveyed from a bibliographical point of view. A brief review of historical sources is presented, followed by a discussion of the contemporary organizations, both international and national, active in the field. Emphasis is placed on the publishing programs and projects, maps, atlases, symposia, reports, and other literature sponsored or stimulated by these organizations. Regional bibliographical surveys for East Africa, India, and the Soviet Union are also noted. Pertinent aspects of bibliographies, indexes, abstracts, library card catalogs and accession lists, and other resources are listed, with emphasis on the various subject headings and other approaches to them. Throughout, the sources of information are approached from a multidisciplinary and interdisciplinary viewpoint.  相似文献   
74.
75.
76.
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   
77.
78.
Physician information seeking: improving relevance through research   总被引:1,自引:0,他引:1  
Health sciences libraries have considerable potential as resources for both formal continuing professional education, as well as the informal continuing education that results from the professional's efforts to solve problems in daily practice. While there is a growing interest in making the resources of health sciences libraries more accessible to practitioners on a routine, day-to-day basis, there also needs to be more awareness of how, when, where, and why professionals look for information in the context of practical problems. This paper reviews recent research that identifies the context in which physicians seek information and advice from external sources, the information sources that physicians access, and the factors that influence which particular sources are sought. The results indicate that physicians vary in their information needs, preferences, motivations, and strategies for seeking information. This diversity suggests that health sciences libraries, in their efforts to be more accessible, should consider "market research" to determine the needs, preferences, and use patterns of the library's targeted users. Libraries may also benefit from exploring alternative methods of improving access to their resources.  相似文献   
79.
80.
Zusammenfassung  Zusammen mit drei weiteren Artikeln, die den übergang vom Batch- zum Timesharing-Betrieb, das Unternehmen und die Hardware des TR440 beschreiben, gibt dieser Text einen Rückblick auf Entwicklung und Realisierung des deutschen Gro?rechners TR440 bei AEG-Telefunken und den Nachfolgefirmen. Dieser Teil des Rückblicks besch?ftigt sich mit der Software und der Software-Entwicklung für den TR440, insbesondere in den Jahren 1965 bis 1974. Es werden technische Highlights der Software behandelt und Einblicke in die Software-Entwicklung selbst gegeben, insbesondere auch Hintergrundinformationen zu Einflüssen, Verantwortungen und Entscheidungen. Der Artikel beginnt mit dem TR4, dem Vorg?nger des TR440, und endet mit den Aktivit?ten für einen TR440-Nachfolger. CR subject classification  K.1 ; K.2 ; K.6 ; D.2 ; D.3 ; D.4 ; D.2.9  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