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   33728篇
  免费   1226篇
  国内免费   16篇
  34970篇
  2020年   411篇
  2019年   448篇
  2018年   632篇
  2017年   651篇
  2016年   712篇
  2015年   455篇
  2014年   611篇
  2013年   2885篇
  2012年   1128篇
  2011年   1163篇
  2010年   788篇
  2009年   778篇
  2008年   1102篇
  2007年   1071篇
  2006年   974篇
  2005年   858篇
  2004年   886篇
  2003年   803篇
  2002年   842篇
  2001年   896篇
  2000年   928篇
  1999年   727篇
  1998年   433篇
  1997年   364篇
  1994年   332篇
  1993年   326篇
  1992年   570篇
  1991年   515篇
  1990年   543篇
  1989年   517篇
  1988年   504篇
  1987年   501篇
  1986年   484篇
  1985年   517篇
  1984年   445篇
  1983年   389篇
  1982年   346篇
  1981年   321篇
  1979年   482篇
  1978年   378篇
  1977年   335篇
  1975年   401篇
  1974年   445篇
  1973年   405篇
  1972年   362篇
  1971年   324篇
  1969年   338篇
  1968年   375篇
  1967年   331篇
  1966年   327篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
102.
103.
This paper describes an amplifier for an electroencephalograph with gain of 1×104 to 1×106 and made entirely of commercially available IC components. The two-stage amplifier has a preamplifier stage with fixed gain of 1000, and a second stage with variable gain from 1 to 100. The final stage, an anti-aliasing filter, adds a gain of 10 to the signal. The circuit has high common mode rejection, low input bias current, very low noise characteristics, low offset voltages, and offset nulling capability built into the circuit.  相似文献   
104.
A unique relationship exists between physicians and philosophers — one that expands on the constructive potential of the liaison between physicians and, for example, theologians, on the one hand, or, social workers on the other. This liaison should focus in the scientific aspects of medicine, not just the ethical aspects. Philosophers can provide physicians with a perspective on both the philosophy and the history of medicine through the ages — a sense of how medicine has adapted to the social cultural and ethical needs of each period. This perspective, while emphasizing medicine asscience, should not be limited to matters of methodology, or to criteria for distinguishing science from other intellectual pursuits, but should be concerned also with the history, sociology and politics of science. Both physicians and philosophers stand to gain from a strengthening of their active liaison now as never before; but most of all, the public will be the beneficiary.  相似文献   
105.
Fear of Success (FOS) was originally conceived as a unidimensional motive. However, there is both theoretical and empirical support for the hypothesis that FOS is multidimensional. We factor analyzed the responses of 236 undergraduates to twenty-oneConcern Over the Negative Consequences of Success items and found four factors. Our four factors show considerable overlap with dimensions based on theoretical accounts of FOS etiology as well as with the factor structures obtained from two other factor analytic studies. Thus, there is converging evidence that FOS is multidimensional. The relationship between multidimensional FOS and a multidimensional approach to achievement motivation is discussed.  相似文献   
106.
The role of lateral masking in more rapid performance improvement with peripheral than with central precuing was investigated. A peripheral precue to the inside of the target location provided less masking at zero precue-target delay than a precue to the outside (experiment 1) or a precue involving a partial target at the target location (experiment 2). There was no significant interaction between precue-target delay and precue type in a comparison of inside precues and precues involving a briefly-brightened box around the target location, although overall performance was significantly poorer with the latter (experiment 3). Performance was better at short precue-target delays with inside precues than with central precues (experiment 4), yet it did not improve significantly more rapidly. Minimizing lateral masking with peripheral precues thus eliminates the dramatic performance improvement sometimes observed across short precue-target delays, causing performance to be consistently better than with central precues across these delays.  相似文献   
107.
Our goal was to test whether current hemisphere predominance is a predictor of scores on standardized measures of personal optimism and preference for risk. In two between-subject experiments, current hemisphere predominance was measured by the direction and extent of line bisecting errors. Pearson correlations and median splits of the line bisecting errors showed significantly greater personal optimism and preference for risk with left hemisphere predominance. These results support previous research in which manipulation of hemisphere predominance produced similar effects on personal optimism in normal individuals and on risk taking in lesioned and normal samples. We conclude that the association of optimism and risk with left hemisphere predominance can be observed in resting as well as in manipulated situations.  相似文献   
108.
Post SG 《America》1992,167(18):453-455
  相似文献   
109.
Forty-one nonpsychiatric subjects, 38 probands with schizophrenia, and 99 of their relatives were studied. Oculomotor functioning was bimodally distributed for probands and relatives. Oculomotor dysfunction was not present in all families with a schizophrenic proband. In those families in which it was present, there were significant phenotypic correlations between oculomotor functioning and schizophrenia-related characteristics. The patterns of familial resemblance in the families in whom oculomotor dysfunction was present were consistent with nonadditive genetic variance contributing both to oculomotor dysfunction and to the relationship between oculomotor dysfunction and clinical symptoms. These results suggest that schizophrenia may be etiologically heterogeneous and that oculomotor dysfunction may help to identify nonadditive genetic variance for this disorder.  相似文献   
110.
We examined the role of reporting bias in hypnotic negative hallucinations by using a paradigm in which reporting bias was assessed independently of perceptual change. In Experiment 1, highly hypnotizable subjects reported significant loudness reductions when tested for hypnotic deafness. Later, however, these subjects biased their reported loudness reductions in the absence of perceptual change, and their reporting bias scores were almost as large as their hypnotic deafness reports. Subjects also biased their ratings of strategy use. In Experiment 2, ratings of blindness given in response to a hypnotic negative visual hallucination suggestion were significantly correlated with reporting bias scores obtained in this paradigm. Although hypnotic blindness and hypnotic deafness correlated significantly, the partial correlation between these variables was nonsignificant when reporting bias scores were statistically controlled. Theoretical implications are discussed.  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