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   52753篇
  免费   1471篇
  国内免费   26篇
  2020年   395篇
  2019年   519篇
  2018年   3998篇
  2017年   3321篇
  2016年   2891篇
  2015年   681篇
  2014年   682篇
  2013年   2750篇
  2012年   1675篇
  2011年   3394篇
  2010年   3094篇
  2009年   2171篇
  2008年   2562篇
  2007年   3059篇
  2006年   869篇
  2005年   945篇
  2004年   895篇
  2003年   754篇
  2002年   735篇
  2001年   1102篇
  2000年   1128篇
  1999年   809篇
  1998年   365篇
  1997年   324篇
  1996年   311篇
  1995年   328篇
  1992年   645篇
  1991年   597篇
  1990年   581篇
  1989年   548篇
  1988年   546篇
  1987年   485篇
  1986年   487篇
  1985年   536篇
  1984年   434篇
  1983年   400篇
  1982年   320篇
  1979年   475篇
  1978年   332篇
  1976年   322篇
  1975年   364篇
  1974年   432篇
  1973年   463篇
  1972年   403篇
  1971年   345篇
  1970年   320篇
  1969年   339篇
  1968年   417篇
  1967年   376篇
  1966年   365篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
931.
932.
933.
934.
935.
Although cerebral anoxia is not thought to be responsible for triggering near-death experiences (NDEs), the issue is not so clear in the case of hypercapnia. Detection of normal blood gases in Michael Sabom's (1982) case study seems to be the major reply to suggestions that hypercapnia may have a causal role in NDEs. We argue, however, that routine arterial measures of blood gases are not a reliable indicator of cerebral levels.  相似文献   
936.
In this article the perspective shifts to the “upstream” end of the agricultural knowledge and information system (AKIS). Because knowledge policy and strategic decision-making are not the prerogative of the public sector, organizations such as cooperative unions and multinational companies are included. After considering the influence of the changing environment on the nature of the AKIS, the role of knowledge management and policy in the emerging knowledge and information market is examined. Special attention is given to public and private R&D. The article then looks where information technology (IT) fits in and what considerations determine strategic investment in IT projects and sustained services. Some of the European experiences with this strategic investment are evaluated.  相似文献   
937.
Despite demonstrations of the utility and cost effectiveness of behavioral programming, such techniques are not commonly employed in psychiatric inpatient settings. Several explanations for this have been proposed, including inadequate levels of training and competence in behavioral programming among prevalent treatment staff. This study employed a multiple choice inventory to assess behavioral knowledge among subjects representing several direct care disciplines commonly found in inpatient psychiatric settings. The results support assertions of relatively low levels of behavioral knowledge among disciplines that are most prevalent in such settings. The implications of these results for initiatives to enhance behavioral knowledge and skills are discussed.  相似文献   
938.
Three inexpensive text-to-speech synthesizers are described, intelligibility data from a pilot experiment are reported, and software is offered that has been written to facilitate the phonemic programming of the Heathkit-Votrax synthesizer.  相似文献   
939.
940.
A system of interfaces for the Commodore 64 (C-64) microcomputer for use in the operant laboratory is described. This system frees the experimenter from limitations on the number of I/O lines available on the user port of the C-64 and offers the control of operant chambers for a low cost. Subroutines in machine code to control the interfaces, offering millisecond timing of external events, are presented. A sample BASIC program demonstrates how the subroutines are called from BASIC to run a simple discrimination experiment.  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