全文获取类型
收费全文 | 30407篇 |
免费 | 474篇 |
国内免费 | 47篇 |
专业分类
教育 | 21602篇 |
科学研究 | 2863篇 |
各国文化 | 291篇 |
体育 | 2512篇 |
综合类 | 39篇 |
文化理论 | 275篇 |
信息传播 | 3346篇 |
出版年
2021年 | 287篇 |
2020年 | 460篇 |
2019年 | 634篇 |
2018年 | 899篇 |
2017年 | 986篇 |
2016年 | 885篇 |
2015年 | 559篇 |
2014年 | 752篇 |
2013年 | 5724篇 |
2012年 | 724篇 |
2011年 | 799篇 |
2010年 | 624篇 |
2009年 | 584篇 |
2008年 | 664篇 |
2007年 | 660篇 |
2006年 | 583篇 |
2005年 | 513篇 |
2004年 | 480篇 |
2003年 | 472篇 |
2002年 | 501篇 |
2001年 | 541篇 |
2000年 | 530篇 |
1999年 | 533篇 |
1998年 | 276篇 |
1997年 | 294篇 |
1996年 | 350篇 |
1995年 | 285篇 |
1994年 | 299篇 |
1993年 | 270篇 |
1992年 | 430篇 |
1991年 | 420篇 |
1990年 | 440篇 |
1989年 | 420篇 |
1988年 | 388篇 |
1987年 | 348篇 |
1986年 | 372篇 |
1985年 | 433篇 |
1984年 | 355篇 |
1983年 | 368篇 |
1982年 | 298篇 |
1981年 | 294篇 |
1980年 | 259篇 |
1979年 | 387篇 |
1978年 | 305篇 |
1977年 | 285篇 |
1976年 | 246篇 |
1975年 | 199篇 |
1974年 | 196篇 |
1973年 | 193篇 |
1972年 | 178篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
C A Perry 《Bulletin of the Medical Library Association》1990,78(3):271-282
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
82.
Tseng SC Arcand JL Brugger JM Finn M Olson AJ Somers S 《Library resources & technical services》1990,34(2):139-157
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
83.
Hafner AW 《Special libraries》1990,81(4):305-308
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
84.
Edwards AJ 《Medical reference services quarterly》1990,9(4):27-42
This article discusses HIV infection in terms of the risk manager's information needs in the health care environment. The malpractice problem, increasing workman's compensation suits, the greater role of the ombudsman, implementation of the National Practitioner Data Bank, and the Joint Commission on Accreditation of Health Care Organizations' (JCAHO) emphasis on clinical excellence are conditions which have given greater importance to the risk manager's position. Included in this article are hedges to retrieve various components of risk management and a select bibliography from AIDSLINE. 相似文献
85.
86.
87.
88.
Sanford G. THATCHER 《Learned Publishing》2008,21(4):278-284
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
89.
90.
V. A. Frolova S. K. Khasenova T. Sh. Kubieva O. A. Rog 《Scientific and Technical Information Processing》2008,35(2):104-106
This paper discusses the evaluation of scientific activity with the help of some scientometric indices, in particular, a citation index. The information massif of the bibliographic database of citations to domestic publications of Kazakh authors is statistically described. 相似文献