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   17958篇
  免费   1611篇
  国内免费   1217篇
  2023年   221篇
  2022年   218篇
  2021年   327篇
  2020年   567篇
  2019年   657篇
  2018年   627篇
  2017年   747篇
  2016年   759篇
  2015年   480篇
  2014年   616篇
  2013年   1999篇
  2012年   416篇
  2011年   521篇
  2010年   415篇
  2009年   636篇
  2008年   812篇
  2007年   842篇
  2006年   821篇
  2005年   690篇
  2004年   598篇
  2003年   513篇
  2002年   459篇
  2001年   298篇
  2000年   276篇
  1999年   238篇
  1998年   189篇
  1997年   158篇
  1996年   134篇
  1995年   126篇
  1994年   119篇
  1993年   102篇
  1992年   80篇
  1991年   54篇
  1990年   58篇
  1989年   32篇
  1988年   44篇
  1987年   29篇
  1985年   380篇
  1984年   421篇
  1983年   346篇
  1982年   455篇
  1981年   445篇
  1980年   445篇
  1979年   401篇
  1978年   456篇
  1977年   359篇
  1976年   359篇
  1975年   275篇
  1974年   278篇
  1973年   236篇
排序方式: 共有10000条查询结果,搜索用时 296 毫秒
241.
242.
243.
驾驶员心理品质检测中的杆型人形图法   总被引:1,自引:0,他引:1  
在汽车驾驶员心理品质检测研究中,我们根据数学中的多变量图分析方法,并汲取简笔画的优点,用19个人形图变量代表检测所得的17种心理品质数据,来具体、形象地再现每个驾驶员心理品质变量的整体关系。这对于检测结果的分类或进行系统化分析具有重要的实用意义。  相似文献   
244.
Arthur Peacocke 《Zygon》1993,28(4):469-484
Abstract. Variable judgments, both negative and positive, have been made by scientists (mainly physicists and astronomers) on the theological implications of their Findings. It is urged that science and theology are most appropriately related through a critical realist approach. On this basis some implications for our conceptions of God and our scientific perspectives on the created world are explored with respect to both divine Being and divine Becoming. A positive assessment of nature as created concludes the article.  相似文献   
245.
In contemporary American scholarship, interpretation of Aristotle'sRhetoric has become the locus of sustained and sharp controversy. Differing views of theRhetoric and its significance have become tokens in a more general dispute about what rhetoric is or ought to be. This essay examines three central issues that have emerged in this larger arena of controversy: the relationship between Aristotelian and Platonic conceptions of rhetoric, the relationships among rhetoric, ethics, and epistemology in Aristotle, and the placement of rhetoric within Aristotle's system of arts and sciences.  相似文献   
246.
This paper is concerned with the processing of informal arguments, that is, arguments involving probable truth. A model of informal argument processing is presented that is based upon Hample's (1977) expansion of Toulmin's (1958) model of argument structure. The model postulates that a claim activates an attitude, the two components forming a complex that in turn activates reasons. Furthermore, the model holds occurrence of the reason, or possibly the claim and the reason, activates values. Three experiments are described that provide support for the model.This research was supported by the Mellon Foundation and by the Office of Educational Research and Improvement of the Department of Education via an award for the Center for the Study of Learning to the Learning Research and Development Center. The contents of the paper are not necessarily the position of any of these organizations.  相似文献   
247.
248.
The crane's foot: The rise of the pedigree in human genetics   总被引:1,自引:1,他引:0  
The standard pedigree used by geneticists is intimately connected to the history of genetics. Pedigrees drawn today are based on standards established in the early decades of the twentieth century. Those standards were established by geneticists who pursued an active interest in eugenics. The slightly different standards followed in America vs. England to some extent followed the stronger support of Mendelism by the Americans, as well as the individual preferences of the leading human geneticists in those countries.  相似文献   
249.
An operant simulation of foraging through baited and empty patches was studied with 4 pigeons. On a three-key panel, side keys were designated as patches, and successive opportunities to complete 16 fixed-ratio 10 schedules on side keys were defined as encounters with feeders. In a random half of the patches in any session, some of the fixed-ratio 10 schedules yielded reinforcement (baited feeders) and the other schedules yielded nonreinforcement (empty feeders). In the other half of the patches, all feeders were empty. Pigeons could travel between patches at any time by completing a fixed-ratio schedule on the center key. An optimal foraging model was tested in Experiments 1 and 2 by varying center-key travel time and number of baited feeders in baited patches. The ordinal predictions that number of feeders visited in empty patches would increase with travel time and decrease as number of baited feeders increased were supported, but pigeons visited far more feeders in empty patches than the optimal number predicted by the model to maximize energy/time. In Experiment 3, evidence was found to suggest that the number of empty feeders encountered before the first baited feeder in baited patches is an important factor controlling leaving empty patches.  相似文献   
250.
The substitutability of reinforcers   总被引:5,自引:3,他引:2       下载免费PDF全文
Substitutability is a construct borrowed from microeconomics that describes a continuum of possible interactions among the reinforcers in a given situation. Highly substitutable reinforcers, which occupy one end of the continuum, are readily traded for each other due to their functional similarity. Complementary reinforcers, at the other end of the continuum, tend to be consumed jointly in fairly rigid proportion, and therefore cannot be traded for one another except to achieve that proportion. At the center of the continuum are reinforcers that are independent with respect to each other; consumption of one has no influence on consumption of another. Psychological research and analyses in terms of substitutability employ standard operant conditioning paradigms in which humans and nonhumans choose between alternative reinforcers. The range of reinforcer interactions found in these studies is more readily accommodated and predicted when behavior-analytic models of choice consider issues of substitutability. New insights are gained into such areas as eating and drinking, electrical brain stimulation, temporal separation of choice alternatives, behavior therapy, drug use, and addictions. Moreover, the generalized matching law (Baum, 1974) gains greater explanatory power and comprehensiveness when measures of substitutability are included.  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