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   31974篇
  免费   475篇
  国内免费   22篇
教育   22384篇
科学研究   3281篇
各国文化   338篇
体育   2466篇
综合类   18篇
文化理论   264篇
信息传播   3720篇
  2021年   300篇
  2020年   463篇
  2019年   724篇
  2018年   962篇
  2017年   973篇
  2016年   860篇
  2015年   528篇
  2014年   825篇
  2013年   6264篇
  2012年   780篇
  2011年   783篇
  2010年   590篇
  2009年   627篇
  2008年   706篇
  2007年   641篇
  2006年   585篇
  2005年   538篇
  2004年   482篇
  2003年   462篇
  2002年   445篇
  2001年   580篇
  2000年   510篇
  1999年   475篇
  1998年   277篇
  1997年   288篇
  1996年   321篇
  1995年   302篇
  1994年   271篇
  1993年   303篇
  1992年   447篇
  1991年   427篇
  1990年   422篇
  1989年   426篇
  1988年   363篇
  1987年   422篇
  1986年   395篇
  1985年   439篇
  1984年   379篇
  1983年   351篇
  1982年   299篇
  1981年   275篇
  1980年   252篇
  1979年   385篇
  1978年   323篇
  1977年   264篇
  1976年   249篇
  1975年   232篇
  1974年   227篇
  1973年   216篇
  1971年   214篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
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   
93.
Time series analysis was used to investigate the hypothesis that during acquisition of a motor skill, knowledge of results (KR) information is used to generate a stable internal referent about which response errors are randomly distributed. Sixteen subjects completed 50 acquisition trials of each of three movements whose spatial-temporal characteristics differed. Acquisition trials were either blocked, with each movement being presented in series, or randomized, with the presentation of movements occurring in random order. Analysis of movement time data indicated the contextual interference effect reported in previous studies was replicated in the present experiment. Time series analysis of the acquisition trial data revealed the majority of individual subject response patterns during blocked trials were best described by a model with a temporarily stationary, internal reference of the criterion and systematic, trial-to-trial variation of response errors. During random trial conditions, response patterns were usually best described by a "White-noise" model. This model predicts a permanently stationary, internal reference associated with randomly distributed response errors that are unaffected by KR information. These results are not consistent with previous work using time series analysis to describe motor behavior (Spray & Newell, 1986).  相似文献   
94.
EPIC is a service that provides keyword or subject access to the OCLC Online Union Catalog (OLUC). This capability increases the success rate for title location as well as the potential uses of the OLUC. The features of the EPIC system, application of these features to the OLUC, and specific uses in health sciences libraries are described in this article.  相似文献   
95.
96.
97.
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   
98.
As a gatekeeper to medical literature and a critical link in the delivery of information to physicians, the librarian's role raises the issue of the librarian's professional liability. The paper suggests several ways in which liability may attach to the librarian or the librarian's employers. Although the librarian's personal risk is negligible, the physician's exposure due to ineffective library work is substantial since the courts have held that a physician must keep abreast of progress in his field. Librarians can also become associated with professional liability actions as part of a case against a physician or hospital through the legal doctrine of vicarious liability. The paper concludes by suggesting several proactive steps for health sciences librarians to pursue to insulate themselves from professional liability and to insulate physicians and institutions from vicarious liability.  相似文献   
99.
Information access is central to library and information science, yet explorations of its conceptual nature have been limited. Given the importance of information access to the discipline, there is a need for research to create a better understanding of the concept and its many roles in all activities and behaviors related to information. Drawing on the theoretical work of Elfreda Chatman, this article proposes that the study of information access can be facilitated through the recognition and examination of the physical, intellectual, and social aspects of information access. These types of access are examined through three case studies in terms of different information behaviors and contexts, with a particular focus on the importance of social access. The article also discusses the future roles that considerations of social access can play in research and theory.  相似文献   
100.
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