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   23320篇
  免费   924篇
  国内免费   11篇
  2019年   284篇
  2018年   397篇
  2017年   439篇
  2016年   463篇
  2015年   348篇
  2014年   378篇
  2013年   1886篇
  2012年   670篇
  2011年   700篇
  2010年   431篇
  2009年   414篇
  2008年   544篇
  2007年   585篇
  2006年   510篇
  2005年   472篇
  2004年   455篇
  2003年   458篇
  2002年   476篇
  2001年   771篇
  2000年   744篇
  1999年   556篇
  1998年   226篇
  1996年   237篇
  1995年   208篇
  1992年   467篇
  1991年   464篇
  1990年   456篇
  1989年   414篇
  1988年   440篇
  1987年   393篇
  1986年   401篇
  1985年   413篇
  1984年   323篇
  1983年   310篇
  1982年   225篇
  1981年   227篇
  1979年   368篇
  1978年   264篇
  1977年   237篇
  1976年   221篇
  1975年   298篇
  1974年   369篇
  1973年   395篇
  1972年   303篇
  1971年   294篇
  1970年   289篇
  1969年   261篇
  1968年   370篇
  1967年   322篇
  1966年   293篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
A simple circuit for a digital millisecond timer and event counter is described. The total cost of the unit including all components, a power supply, and an enclosure is less than $30. Daily use in simple reaction time experiments has demonstrated the reliability of the design.  相似文献   
962.
This article describes a new solution to the dilemma faced by investigators who need dedicated computers but cannot afford the cost of expensive peripherals. An available software-hardware combination is described that permits users to timeshare expensive peripherals but to have a dedicated microprocessor at their disposal.  相似文献   
963.
A rapid inexpensive technique for changing from intravenous drug self-administration (DSA) to liquid reinforcement is described. Utilizing a standard peristaltic-type infusion pump typically used in DSA experiments and a specially designed drinking cup, the changeover from intravenous DSA to liquid reinforcement can be accomplished in a few minutes at a cost of less than $10.  相似文献   
964.
965.
966.
967.
Subjects were presented either with models set at an angle or with photographs of such models. They were required to remember the orientation (or the depicted orientation) and to reproduce it using similar models placed on a turntable. It was found that the subjects showed a systematic tendency to reproduce the settings of the depicted models as being closer to the one of the two ‘typical’ settings (profile and face on) than they really were. The continuum between the two ‘typical’ settings appeared to be divided into two unequal zones and the sense of the error made was dependent on the zone from which the stimulus originated. No similar effects were observed in the responses made to models.  相似文献   
968.
A theoretical framework is proposed for understanding perceptual skills in their functional context. Pictorial perception is construed as a functionally specialised skill whose pervasive importance in modern education derives from the proliferation of pictorial materials in Western culture. Drawing on cross-cultural research, the major components of the skill are identified as (1) detection of appropriate contexts for its application, (2) selection of a limiting frame of reference, (3) use of conventional criteria of fidelity to recognise depicted items, (4) sensitivity to impoverished depth cues, (5) an expectation of finding in the picture most of the information necessary for its disambiguation, and (6) various assumptions about the range of cognitive inferences that may legitimately be made ‘beyond the information given’. Training studies are interpreted as suggesting that the skill can be enhanced through guided experience.  相似文献   
969.
Typically, citizens lack relevant information concerning possible consequences of proposed environmental projects. Despite federal requirements for citizen participation in decisions about proposed roadway projects, no systematic procedures exist for educating citizens as to the possible consequences of such projects. The effects of a consequence analysis procedure on community residents' verbal statements about the favorability of a proposed roadway project were assessed. The consequence analysis procedure involved asking residents to rate the desirability and magnitude of each of 48 possible consequences of the proposed roadway project. Following the intervention, overall ratings of favorability of the project changed for nine of ten residents. Community residents' ratings of the quality of participants' justifications of their position on the roadway issue provided evidence of generalization to this collateral behavior.  相似文献   
970.
Feedback and feedback plus points toward a course grade were applied to the attentional behaviors (defined as the ability to identify the semantic base of text passages) of 30 undergraduate students participating in a reading comprehension development program. Correct underlining was increased, extraneous underlining was decreased, and postreading comprehension test scores improved as a result of the procedures. Scores on a standardized test of reading comprehension also increased significantly.  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