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   21546篇
  免费   901篇
  国内免费   13篇
  2020年   252篇
  2019年   238篇
  2018年   411篇
  2017年   354篇
  2016年   381篇
  2015年   247篇
  2014年   356篇
  2013年   1543篇
  2012年   616篇
  2011年   670篇
  2010年   351篇
  2009年   435篇
  2008年   588篇
  2007年   582篇
  2006年   539篇
  2005年   475篇
  2004年   455篇
  2003年   446篇
  2002年   408篇
  2001年   794篇
  2000年   792篇
  1999年   583篇
  1998年   233篇
  1997年   212篇
  1992年   483篇
  1991年   422篇
  1990年   485篇
  1989年   407篇
  1988年   384篇
  1987年   365篇
  1986年   387篇
  1985年   440篇
  1984年   338篇
  1983年   284篇
  1982年   219篇
  1981年   191篇
  1979年   322篇
  1978年   256篇
  1977年   204篇
  1976年   199篇
  1975年   298篇
  1974年   345篇
  1973年   350篇
  1972年   274篇
  1971年   241篇
  1970年   208篇
  1969年   228篇
  1968年   288篇
  1967年   251篇
  1966年   272篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
33.
34.
35.
Public goods theories highlight an incentive system that rewards ‘free riding’ on the contributions of early contributors toward collective actions. However, because such theories focus on creation of the good, they may underestimate returns that accrue to early contributors subsequent to the good's realization. The concept of formative investment is introduced here to describe the extent to which organizations help to create public goods such as interorganizational linkages like participatory federations. Data from the CEOs of 48 organizations involved in a participatory federation were used to assess how an organization's level of formative investment is related to later patterns of dependency and interaction among federation members. Findings suggest that from a long‐term perspective, and for goods that involve communication and interaction, the incentive structure may not be so favorable for free riders. To the extent that organizations with high formative investment have the capability to envision the future and communicate that vision to potential federation partners, they may be able to both reduce free riding and secure for themselves advantageous positions in the subsequent network of relations.  相似文献   
36.
37.
The token economy has been the primary model for the behavioral management of inpatient populations. However, this basically operant approach seldom emphasizes the development of cognitive-coping skills to help patients more effectively manage stressors that result in hospitalization. The Therapeutic Contract Program (TCP) is described as an inpatient-treatment strategy that is designed to help foster such cognitive-coping and self-control skills. While external structure is provided by components of this program, subprograms of the TCP have as their goal the development of internally-attributed coping skills and self-perceptions of competence. This preliminary report describes the structure of the TCP, as well as planned and in-progress measures of program participation and treatment outcome.  相似文献   
38.
A series of stereograms are presented which demonstrate that texture boundaries can strongly influence the perception of discontinuities between neighbouring three-dimensional (3-D) surfaces portrayed by means of stereo cues. In these demonstration figures, no stereo information is available in the immediate vicinity of the boundary between the two 3-D stereo surfaces because all texture in that region is removed in one eye's view. On the other hand, various forms of texture boundary information are provided in the resulting monocular region. This stimulus paradigm is used to explore the question: what influence does texture boundary information have on the nature of the perceived 3-D surface that is interpolated between two stimulus regions which carry stereo cues? It is shown that if a clear-cut texture boundary is present in the monocular region then this is used by the human visual system to fix the perceived location of 3-D crease and step surface discontinuities between the stereo regions. Collett (1985) explored this issue with a similar methodology and reported weak and unreliable assistance from monocular texture boundaries in helping shape 3-D stereo surface discontinuities. The strong and robust phenomena demonstrated here seem to rely on two main differences between the present stimuli and those of Collett. In the present stimuli, figurally continuous textures containing strong texture boundaries are used, together with a technique for minimising the complications, including binocular rivalry, that arise from the borders of the stimulus regions present in only one half of each stereogram.  相似文献   
39.
40.
THE SOCRATIC METHOD AND PHILOSOPHY FOR CHILDREN   总被引:1,自引:0,他引:1  
  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