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   21879篇
  免费   295篇
  国内免费   36篇
教育   15107篇
科学研究   2448篇
各国文化   214篇
体育   2021篇
综合类   11篇
文化理论   191篇
信息传播   2218篇
  2021年   202篇
  2020年   306篇
  2019年   428篇
  2018年   585篇
  2017年   580篇
  2016年   551篇
  2015年   382篇
  2014年   511篇
  2013年   3888篇
  2012年   465篇
  2011年   494篇
  2010年   434篇
  2009年   361篇
  2008年   421篇
  2007年   415篇
  2006年   381篇
  2005年   342篇
  2004年   355篇
  2003年   354篇
  2002年   305篇
  2001年   579篇
  2000年   423篇
  1999年   386篇
  1998年   187篇
  1997年   224篇
  1996年   237篇
  1995年   198篇
  1994年   231篇
  1993年   192篇
  1992年   318篇
  1991年   323篇
  1990年   313篇
  1989年   326篇
  1988年   273篇
  1987年   267篇
  1986年   280篇
  1985年   321篇
  1984年   253篇
  1983年   270篇
  1982年   228篇
  1981年   212篇
  1980年   202篇
  1979年   311篇
  1978年   236篇
  1977年   215篇
  1976年   189篇
  1975年   181篇
  1974年   184篇
  1973年   160篇
  1971年   162篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
81.
82.
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   
83.
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   
84.
85.
86.
87.
88.
We theorize about the strategic alignment of computing with organizational mission, using the Commonwealth of Pennsylvania's efforts to pursue digital government initiatives as evidence. To do this we draw on a decade (1995–2004) of changes in Pennsylvania to characterize how a state government shifts from an organizational to an enterprise perspective regarding computing. We document and analyze the strategic and operational aspects of a series of information and communications technology (ICT) planning efforts to highlight the nature and roles of strategic alignment used to achieve this transition. Findings from this analysis mark the importance of combining several approaches to strategic planning regarding the adoption and application of ICT.  相似文献   
89.
90.
At this critical point in its development as a burgeoning market economy ensconced within a socialist political system, China faces a dilemma in becoming a fully‐fledged player in the copyright arena. Over the past two decades, China has made great strides in creating a legal and governmental framework for the administration and enforcement of copyright. But its implementation has left much to be desired, owing partly to inadequate resources of money and personnel, partly to insufficiently harsh penalties for infringement, partly to cumbersome procedures required to bring action against infringers, and partly to a general cultural tolerance for practices that run contrary to cultivating a broad‐based respect for copyright. This article proposes that a balance of pressure and encouragement is likely to have the best chances of success in overcoming these problems and ensuring that China will become fully welcomed into the international publishing community.  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