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   60021篇
  免费   1610篇
  国内免费   27篇
  2020年   427篇
  2019年   549篇
  2018年   4023篇
  2017年   3361篇
  2016年   2957篇
  2015年   750篇
  2014年   766篇
  2013年   3507篇
  2012年   1825篇
  2011年   3550篇
  2010年   3189篇
  2009年   2291篇
  2008年   2765篇
  2007年   3247篇
  2006年   1135篇
  2005年   1177篇
  2004年   1093篇
  2003年   1006篇
  2002年   990篇
  2001年   1222篇
  2000年   1262篇
  1999年   932篇
  1998年   503篇
  1997年   462篇
  1996年   444篇
  1995年   447篇
  1994年   417篇
  1992年   763篇
  1991年   708篇
  1990年   668篇
  1989年   650篇
  1988年   639篇
  1987年   593篇
  1986年   600篇
  1985年   655篇
  1984年   570篇
  1983年   538篇
  1982年   463篇
  1980年   406篇
  1979年   587篇
  1978年   478篇
  1977年   437篇
  1976年   454篇
  1975年   493篇
  1974年   569篇
  1973年   588篇
  1972年   496篇
  1968年   478篇
  1967年   413篇
  1966年   406篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
911.
912.
The results of two experiments involving the matching of unfamiliar, nameless shapes (Gibson forms) indicated that a visual representation of a brief (30-100 ms) stimulus survives in a Short-Term Visual Memory (STVM) for 6 s or more after the onset of a pattern mask. On the basis of these results a possible alternative to Sperling's (1967) model for short-term memory for visual stimuli was presented. In this model it is assumed that recognition processes occupy several hundred milliseconds and continue after the arrival of the mask using the information available in STVM.  相似文献   
913.
Conventional procedures do not provide a practical method for the administration of volatile anesthetics such as halothane to rats while they are undergoing stereotaxic surgery. This paper describes a device which meets this need and which is easy and inexpensive to construct. A two-piece cylinder cut from the mouth of a polyethylene bottle forms a closed system around the muzzle of a rat and does not interfere with the stereotaxic apparatus or with the operation itself. The cylinder is attached to any standard device for the dispension of volatile anesthetics. The immediate advantage is that behavioral assesaments can be made relatively soon after surgery.  相似文献   
914.
915.
916.
Differential vocal emphasis in the tape-recorded instruction reading for a standard person perception task was manipulated by mechanically raising or lowering the volume of the key words describing the success or failure response alternatives on the rating scale. In a series of three experiments, Ss exposed to success emphasis in the instructions rated the stimulus persons as more successful than did Ss exposed to failure emphasis. This trend was reversed for Ss who listened twice to the instructions. None of the Ss reported awareness of the influence attempt.  相似文献   
917.
Robert W. Latzer 《Synthese》1972,24(1-2):236-280
Temporal betweenness in space-time is defined solely in terms of light signals, using a signalling relation that does not distinguish between the sender and the receiver of a light signal. Special relativity and general relativity are considered separately, because the latter can be treated only locally. We conclude that the (local) coherence of time can be described if we know only which pairs of space-time points are light-connected. Other consequences in the case of special relativity: (1) a categorical axiom system exists in terms of nondirected light connection alone, with neither particle nor time order as a primitive concept, though we do not actually present the axioms; (2) any concept definable by coordinates is also definable in terms of nondirected light signals if and only if it is invariant under Lorentz transformations, translations, dilations, space reflections, and time reflections; and (3) any transformation of space-time (not necessarily continuous) which preserves nondirected light connection is a product of transformations just listed above. The bulk of the paper is devoted to proving that the definitions we give correspond to their intended interpretations in the usual space-time continua.  相似文献   
918.
919.
920.
The asymptotic distributions of response probabilities in the Audley-Jonckheere learning model, as applied to the two-choice learning situation, are described for (1) the experimenter-controlled events model, (2) the subject-controlled events model, and (3) the experimenter-subject-controlled events model.  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