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   13439篇
  免费   285篇
  国内免费   1篇
  13725篇
  2020年   170篇
  2019年   163篇
  2018年   292篇
  2017年   276篇
  2016年   285篇
  2015年   217篇
  2014年   244篇
  2013年   1023篇
  2012年   418篇
  2011年   440篇
  2010年   266篇
  2009年   222篇
  2008年   362篇
  2007年   349篇
  2006年   319篇
  2005年   271篇
  2004年   259篇
  2003年   234篇
  2002年   261篇
  2001年   447篇
  2000年   417篇
  1999年   295篇
  1998年   138篇
  1996年   132篇
  1995年   127篇
  1992年   238篇
  1991年   246篇
  1990年   230篇
  1989年   234篇
  1988年   223篇
  1987年   209篇
  1986年   193篇
  1985年   204篇
  1984年   202篇
  1983年   154篇
  1982年   152篇
  1979年   190篇
  1978年   128篇
  1977年   130篇
  1976年   139篇
  1975年   161篇
  1974年   198篇
  1973年   210篇
  1972年   167篇
  1971年   149篇
  1970年   128篇
  1969年   149篇
  1968年   188篇
  1967年   146篇
  1966年   150篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
131.
Interpersonal anxiety as a function of social class   总被引:1,自引:0,他引:1  
  相似文献   
132.
Let x be ap-component random variable having a multivariate normal distribution with covariance matrix . In this paper, we consider the problem of testing hypotheses of the formH 0: =b 11 + +b m m , whereb i 's are unknown scalars, and i 's are a set of known and simultaneously diagonalizable matrices. This problem has both psychometric and statistical interest, and its basic theory is developed here. Besides, the problem of obtaining likelihood-ratio statistic for testingH 0 is studied, and the statistic obtained in a special case.  相似文献   
133.
Absolute vibrotactile thresholds are determined on the human tongue and compared to corresponding data obtained on the hand. The mucosa of the tongue is devoid of Pacinian corpuscles but the hand is richly with these nerve endings. Summation of energy is characteristic of responses recorded from tissue containing Pacinian corpuscles and absent where the corpuscle is specifically sensitive to mechanical vibration.  相似文献   
134.
135.
Different patterns of figures moving behind a window were viewed by subjects while fixating a point 8.5–11° visual angle NW of the display. With prolonged viewing and small figures, the motion appeared to stop completely. With moving figures which stretched the whole way across the field, perpendicular to the direction of motion, a pulsating or wave motion was experienced. A reduction in the number of moving figures was also reported with all the patterns. When the stimulus motion was stopped, the expected after effect of motion in the opposite direction was usually experienced, although in many cases the stopping of the stimulus motion led to an immediate disappearance of the stimulus figures.  相似文献   
136.
137.
138.
If rats are overtrained on a visual discrimination they generally learn the reversal of the discrimination faster than non-overtrained rats. In position discriminations, however, this effect does not generally hold—indeed several investigators have found overtraining to retard position reversal. One of the important differences between the two types of problem seems to be the presence of irrelevant cues in visual discriminations, and their absence in position discriminations. It is suggested that a second important feature of position discriminations is that overtraining usually causes control of the maze running habit to be transferred from external to proprioceptive stimuli, and that successful reversal cannot normally occur until external control is re-established. In two experiments a study by Krechevsky and Honzik (1932) is repeated with certain modifications, with results that support this hypothesis; and a third experiment provides direct evidence of transfer to proprioceptive control in a T-maze. It is shown that this analysis will explain the apparently conflicting results of all recent position reversal experiments.  相似文献   
139.
Pascal routines are described for several real-time operations on Macintosh computers. Methods are presented for millisecond timing and for high-speed transfer of arbitrary bit-image displays to the screen. All routines are based on Toolbox procedures available on virtually all Macintosh computers.  相似文献   
140.
The orienting response (OR) is a specific behavioral act directed towards extraction of information from the environment. Head and eye movements represent only the tip of the iceberg of internal responses, which includes vascular modifications, EEG changes, and event-related potentials. Two mechanisms of the OR have to be differentiated: voluntary and involuntary. In the event-related potential, such a differentiation is expressed in mismatch negativity (involuntary effect) and processing negativity (voluntary effect). Single unit studies have shown that hippocampal neurones are simulating specific features of the OR as a response to novelty. Repeated presentation of stimuli results in a selective habituation of novelty detectors in hippocampus and of the OR. The trace of a standard stimulus formed at the level of hippocampal neurones matches the features of the standard stimulus and can be called a “neuronal model of the stimulus.” The OR is triggered by mismatch between the test stimulus and the elaborated neuronal model, and is activated by verbal instruction, by reinforcement during the initial stage of conditioned reflex elaboration, and by differentiation of signal and non-signal stimuli. A promising new area of practical application of the OR lies in the evaluation of a corridor of optimal functional state for efficient computer-based learning. Registration of the OR and defensive responses can be used for an objective evaluation of the functional state of the student, or, in a wider sense, of the industrial operator. New avenues of OR research are opened by recent techniques that isolate single-trial event related potentials, and their correlation with autonomic and behavioral manifestations of the OR. The combination of single unit recording with such isolated event related potentials can elucidate the neuronal basis of OR generation. Intracellular recording combined with dye injection can be used for analysis of the synaptic contacts involved in generation of the OR. Integration of macro and micro levels of OR organization can be achieved in a computerized model that can be used for simulation and planning of experiments. A step-by-step improvement of the model will accumulate knowledge about the OR as an important mechanism of information processing.  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