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   25853篇
  免费   494篇
  国内免费   2篇
  26349篇
  2020年   296篇
  2019年   385篇
  2018年   512篇
  2017年   461篇
  2016年   548篇
  2015年   377篇
  2014年   450篇
  2013年   2157篇
  2012年   817篇
  2011年   898篇
  2010年   540篇
  2009年   607篇
  2008年   728篇
  2007年   813篇
  2006年   705篇
  2005年   632篇
  2004年   666篇
  2003年   600篇
  2002年   571篇
  2001年   672篇
  2000年   683篇
  1999年   510篇
  1998年   338篇
  1997年   263篇
  1996年   280篇
  1995年   259篇
  1994年   263篇
  1993年   234篇
  1992年   398篇
  1991年   390篇
  1990年   397篇
  1989年   355篇
  1988年   345篇
  1987年   328篇
  1986年   330篇
  1985年   353篇
  1984年   278篇
  1983年   302篇
  1982年   246篇
  1979年   340篇
  1978年   320篇
  1977年   232篇
  1975年   285篇
  1974年   310篇
  1973年   335篇
  1972年   286篇
  1971年   270篇
  1968年   299篇
  1967年   296篇
  1966年   249篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
151.
The present study based on the indirect Clausen-test using NTA and PHA as antigens contributed to therapy control and possibly prognosis assessment rather than to immunological differential diagnosis.  相似文献   
152.
Reviews     
J. O. Ramsay 《Psychometrika》1984,49(2):281-283
  相似文献   
153.
154.
Food-deprived pigeons pecked a key under a schedule in which grain was made available after the seventieth peck. In each sequence of 70 responses, either the first, middle, or final response was followed by electric shock. Before the first response of each sequence, each response on a second key changed the color of the food key and the schedule of shock that was correlated with the food key color. Each pigeon preferred a schedule of shock, in that each of the three shock schedules did not occur equally often. The preferred shock schedule and the strength of the preference varied among the pigeons. The overall rate of responding by a pigeon under a given shock schedule was directly related to the pigeon's relative preference for that schedule, except when shock after the first response in the sequence was the most preferred schedule.  相似文献   
155.
156.
In the first of two experiments, it was demonstrated that an air puff elicited a reliable startle reflex in rats which showed no habituation over 50 trials. In the second study an attempt was made to measure an emotional response by recording startle reactions to the air puff during presentation of a presumed fear-eliciting CS. It was concluded that the air-puff-elicited startle reflex can be employed as an indirect measure of a hypothetical emotional response.  相似文献   
157.
The electromyogram (EMG) recorded with surface electrodes was examined using a triggered oscilloscope technique. When all but the high-amplitude waveforms in a given segment of activity were excluded from analysis, it was found that the duration of the remaining waveforms was specific to the muscle that produced them. That is, waveforms of a given duration were recorded whenever conventional indices-observable contraction, joint movement. needle recordings-showed activity in a specific muscle. This led to the suggestion that waveform duration might be used to validate the surface EMG. The suggestion. which is limited by the need to control posture and electrode placement, both of which may influence waveform duration, was illustrated in application to psychological research.  相似文献   
158.
Twenty-eight pigeons were given discrimination training. Four groups were run in which for 0, 2, 4 and 9 sessions of training colour was an irrelevant cue and tone was relevant. Generalization tests were given in extinction; the training colour (C1) and another colour (C2) were presented with tone (T) and noise (N). Responding to these four stimulus combinations, TC1, TC2, NC1 and NC2, allowed the assessment of control by colour and tone. A reduction of control by colour and an increase in control by tone were found to be positively related to the amount of training with colour irrelevant. Tests showed a strong inverse relationship between control by colour and tone.  相似文献   
159.
160.
Book reviews     
Encyclopaedia of Linguistics, Information and Control. Edited by A. R. Meetham with the assistance of R. A. Hudson. Oxford: Pergamon Press. 1969. Pp. xiv + 718. 300s.

The Biological Basis of Personality. By H. J. Eysenck. Springfield: Thomas. 1968. Pp. xv + 399. $18.50.

Scientific Basis of Dvug Dependence. Biological Council Symposium. Edited by H. Steinberg. London: Churchill. 1969. Pp. 429. 100s.

Minnesota Symposia on Child Psychology, Vol. 2. Edited by John P. Hill. Minneapolis: University of Minnesota Press. 1969. Pp. viii + 172.

Memory and Attention: an introduction to human information processes. By Donald A. Norman. Chichester, Sussex: John Wiley. 1969. Pp. ix + 201. 84s. (cloth); 44s. (paper). Verbal Learning and Memory: selected readings. By Leo Postman and Geoffrey Keppel. Harmondsworth: Penguin Books. 1969. Pp. 501. 12s.

Handbuch der Kinderheilkunde. Edited by H. Opitz and F. Schmidt. Rand VIII/I: Neurologie-Psychologic-Psychiatrie. Redigiert von F. Schmidt und H. Asperger. Berlin: Springer Verlag. Pp. 1060. Price DM385, S96.25.

Digital Computing. By R. S. Lehman and D. E. Bailey. London: John Wiley & Sons Ltd. 1969. Pp. xxiv + 303. 79s.

Real-Time Computers. By W. R. Uttal. New York: Harper & Row. 1968. Pp. xiv + 338. 93s.  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