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   175507篇
  免费   7987篇
  国内免费   157篇
  2020年   2785篇
  2019年   3455篇
  2018年   3560篇
  2017年   3977篇
  2016年   4656篇
  2015年   3925篇
  2014年   4823篇
  2013年   23561篇
  2012年   4564篇
  2011年   3646篇
  2010年   3894篇
  2009年   4789篇
  2008年   3932篇
  2007年   3442篇
  2006年   4024篇
  2005年   3969篇
  2004年   3501篇
  2003年   3148篇
  2002年   2947篇
  2001年   3479篇
  2000年   3320篇
  1999年   3267篇
  1998年   2841篇
  1997年   2694篇
  1996年   2617篇
  1995年   2434篇
  1994年   2414篇
  1993年   2347篇
  1992年   2711篇
  1991年   2550篇
  1990年   2407篇
  1989年   2302篇
  1988年   2279篇
  1987年   2268篇
  1986年   2290篇
  1985年   2486篇
  1984年   2582篇
  1983年   2353篇
  1982年   2377篇
  1981年   2368篇
  1980年   2200篇
  1979年   2262篇
  1978年   2208篇
  1977年   2173篇
  1976年   1993篇
  1975年   2073篇
  1974年   2129篇
  1973年   2020篇
  1972年   1622篇
  1971年   1550篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
921.
922.
923.
A computer-controlled system that detects spontaneous activity (locomotion and rearing) and diurnal activity rhythms in small animals is described. Automatic recording of subtotals during test periods provides data about habituation (nonassociative learning). The system is relatively inexpensive to construct. Fabricated from highly reliable circuit components, it provides replicable measures that enable comparisons between different experimental treatments to be made using parametric statistics.  相似文献   
924.
925.
This paper develops hypotheses about the implications of different types of decision for the utilization of different types of systematically produced information: data, research, and analysis. The engineering and enlightenment models found in the knowledge utilization literature prove inadequate for this purpose. We turn to three decision models—routine, incremental, and fundamental–and determine their implied demands for information. We also examine how information might be used in scanning procedures in anticipation of decision regime shifts. The results suggest that patterns of information should differ markedly in each decision context and indicate that there may be an inherent bias against the use of research in decision. Evert A. Lindquist, a doctoral candidate at the Graduate School of Public Policy, University of Calfornia at Berkeley, is completing a dissertation onPolicy Institutes in Canada: The Organization and Relevance of Public Inquiry and will join the faculty of the Department of Political Science at the University of Toronto this fall. Organizations, public policy, and the role of information in decision making are among his primary research interests.  相似文献   
926.
An emergent social science of knowledge applications, drawing on a substantial multidisciplinary literature published over the past twenty-five years, signals an inversion of typical scholarly reasoning about the knowledge-society nexus. Whereas most scholarly research thus far has concentrated on conditions believed to affect the production of scientific and professional knowledge, we pose a new problematic: What must we examine in order to comprehend and consciously shape applications of scientific and professional knowledge to the manifold problems facing contemporary societies? To date, approaches to this problematic have proceeded on the basis of four broadly accepted if abstract theses about the nature of contemporary knowledge systems: subjectivity, corrigibility, sociality, and complexity. Within the boundaries supplied by these commonly accepted theses are unresolved controversies expressed in competing visions of complexity, alternative perspectives of causation, rival images of progress, and conflicting criteria of application.  相似文献   
927.
A technical issue in auditory spatial attention research is how best to provide low-cost, accurate control of the frequency, duration, and location of acoustic signals. Three solutions to the problem are compared: use of the internal oscillator of the Apple lIe, use of a Mountain A/D+D/A card, and use of an external oscillator chip. The unique advantages and drawbacks of each system are discussed. All share some common problems of external speaker interface, timing control, and interface with the software. Hardware and software solutions implemented on the Apple-Psych system are discussed, along with data that demonstrate the precision control achieved with the system.  相似文献   
928.
In this paper, I discuss a number of issues concerning software selection in instructional laboratories. First, I describe several taxonomies of instructional software and argue that the most important dimension of instructional software is that it must be an efficient tool. Second, I discuss some elements of the context of the instructional lab, including sophistication of users. Third, I explore design features, especially those related to ease of learning to use packages. Several other issues are also considered, such as where to find software reviews.  相似文献   
929.
This article presents a simulation-based tutorial system for exploring parallel distributed processing (PDP) models of information processing. The system consists of software and an accompanying handbook. The intent of the package is to make the ideas underlying PDP accessible and to disseminate some of the main simulation programs that we have developed. This article presents excerpts from the handbook that describe the approach taken, the organization of the handbook, and the software that comes with it. An example is given that illustrates the approach we have taken to teaching PDP, which involves presentation of relevant mathematical background, together with tutorial exercises that make use of the simulation programs.  相似文献   
930.
This paper compares several software packages that allow users to create new computer-run experiments, but do not require that users be able to program. Three dimensions are considered: package requirements, ease of learning, and power and flexibility.  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