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   122803篇
  免费   1608篇
  国内免费   239篇
教育   85385篇
科学研究   13327篇
各国文化   1982篇
体育   9235篇
综合类   178篇
文化理论   1053篇
信息传播   13490篇
  2021年   946篇
  2020年   1638篇
  2019年   2546篇
  2018年   3029篇
  2017年   3332篇
  2016年   3350篇
  2015年   2309篇
  2014年   3181篇
  2013年   27226篇
  2012年   2369篇
  2011年   2717篇
  2010年   2330篇
  2009年   2632篇
  2008年   2382篇
  2007年   2104篇
  2006年   2363篇
  2005年   2355篇
  2004年   3031篇
  2003年   2340篇
  2002年   2158篇
  2001年   2003篇
  2000年   1678篇
  1999年   1555篇
  1998年   1454篇
  1997年   1513篇
  1996年   1688篇
  1995年   1472篇
  1994年   1460篇
  1993年   1470篇
  1992年   1485篇
  1991年   1400篇
  1990年   1380篇
  1989年   1320篇
  1988年   1176篇
  1987年   1129篇
  1986年   1148篇
  1985年   1424篇
  1984年   1301篇
  1983年   1278篇
  1982年   1247篇
  1981年   1174篇
  1980年   1157篇
  1979年   1242篇
  1978年   1210篇
  1977年   1123篇
  1976年   1004篇
  1975年   800篇
  1974年   807篇
  1973年   767篇
  1971年   634篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Sequence learning in pigeons was studied in asimultaneous chaining paradigm: all stimuli and the opportunity to respond to each stimulus were available simultaneously. In contrast to the traditionalsuccessive chaining paradigm, a simultaneous chaining paradigm provides no differential feedback following each response (except the last). Subjects were first trained to perform on sequences of two (AB), then three (ABC), and then four colors (ABCD). Performance greatly exceeded that predicted by models of random choice. Generalization to novel arrays of three and four colors was complete. After training with a four-color sequence, the subjects were tested with subsequences consisting of all possible combinations of two and three of the four training colors (e.g., BD, AD, BC, ACD, BCD, etc.). The successful completion of these subsequences showed that the organization of the original sequence did not entail overt pecks to successive elements of that sequence. That subjects can respond accurately on nonadjacent subsets is not readily explained by a chaining theory, or by any theory that assumes that responding to element n provides a cue for responding to element n+1.  相似文献   
992.
Educational technology research and development -  相似文献   
993.
The purpose of this review was to synthesize the research on the relationship between performance on Piagetian tasks of concrete operations and performance on mathematics learning tasks in order to determine whether the Piagetian tasks make useful readiness measures. The research consistently indicates that, while there is a positive correlation between performance on Piagetian tasks and mathematics achievement, many school mathematics tasks can be mastered by children who have not yet developed the reasoning abilities measured by Piagetian tasks. This does not diminish the validity of Piaget's theory, but rather suggests that the kinds of reasoning processes identified by Piaget are not essential in solving many school mathematics tasks.  相似文献   
994.
Financial problems at colleges and universities have led many institutions to initiate extra efforts to obtain extramural funds. One such effort has been the establishment of formula-based research incentive plans. These plans generally utilize the recovery of indirect costs as the basis for allocating additional incentive funds to various areas as an encouragement to obtain additional extramural funds. Data from surveys conducted by the University of Missouri-Kansas City and Ohio University were combined with National Science Foundation reports to provide information about this relatively recent phenomena. The increasing popularity of these plans was shown in that a majority of institutions had such plans in effect during FY 1979. Analyses of the effectiveness of these plans showed no statistically significant differences between institutions with incentive plans and those without such plans, although mean federal research expenditures were approximately 20% greater at those institutions without these incentive plans. The evidence presented indicates that the receipt of federal research funds is not associated with the use of a formula-based research incentive plan.  相似文献   
995.
996.
Three experiments with rat subjects were designed to investigate the possibility that an extinguished saccharin aversion might be reinstated if the animals are made ill with lithium chloride (in the absence of saccharin) following extinction. Although reinstatement can be obtained when the unconditioned stimulus is presented following the extinction of other kinds of conditioned behaviors, the present experiments provided no evidence that an extinguished taste aversion can be reinstated. No reinstatement was observed, even when the aversion had been only partially extinguished and when multiple injections of lithium chloride were administered in an attempt to reinstate the aversion.  相似文献   
997.
We have undertaken a critical appraisal of the current English system of law regulating: (1) Provision of services designed to prevent children coming into care of local authorities, which are the authorised agencies for dealing with children who are abused or neglected. (2) Ways of receiving children into care and also ways of terminating care orders. We question whether, and under what circumstances, care orders are really necessary. (3) Periodic reviews of children in care. We are critical of the English system and look to models in the USA as guides towards the possible reform of English law. We take the same perspective when considering termination of parental rights. In our opinion good laws do not of themselves provide the care and love which a child requires, but they make the caring possible by loved and loving adults. We argue that the law must provide the best possible framework to allow adequate caring by members of the non-legal professions, such as social workers and foster parents. At the same time the law must ensure that the rights of parents and children are protected.  相似文献   
998.
999.
1000.
This study was based on Hovland's four-part statement, “Who says what to whom with what effect,” the rationale for persuasive communication, a theoretical model for modifying attitudes. Part I was a survey of 139 perservice elementary teachers from which were generated the more credible characteristics of metric instructors, a central element in the “who” component of Hovland's model. They were: (1) background in mathematics and science, (2) fluency in metrics, (3) capability of thinking metrically, (4) a record of excellent teaching, (5) previous teaching of metric measurement to children, (6) responsibility for teaching metric content in methods courses and (7) an open enthusiasm for metric conversion. Part II was a survey of 45 mathematics educators where belief statements were synthesized for the “what” component of Hovland's model. It found that math educators support metric measurement because: (1) it is consistent with our monetary system; (2) the conversion of units is easier into metric than English; (3) it is easier to teach and easier to learn than English measurement; there is less need for common fractions; (4) most nations use metric measurement; scientists have used it for decades; (5) American industry has begun to use it; (6) metric measurement will facilitate world trade and communication; and (7) American children will need it as adults; educational agencies are mandating it. With the “who” and “what” of Hovland's four-part statement defined, educational researchers now have baseline data to use in testing experimentally the effect of persuasive communication on the attitude of preservice teachers toward metrication.  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