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   12153篇
  免费   510篇
  国内免费   6篇
  2023年   67篇
  2022年   62篇
  2021年   123篇
  2020年   219篇
  2019年   253篇
  2018年   336篇
  2017年   312篇
  2016年   378篇
  2015年   245篇
  2014年   332篇
  2013年   1322篇
  2012年   570篇
  2011年   565篇
  2010年   416篇
  2009年   420篇
  2008年   591篇
  2007年   563篇
  2006年   505篇
  2005年   433篇
  2004年   469篇
  2003年   427篇
  2002年   416篇
  2001年   184篇
  2000年   199篇
  1999年   188篇
  1998年   189篇
  1997年   158篇
  1996年   109篇
  1995年   147篇
  1994年   145篇
  1993年   132篇
  1992年   125篇
  1991年   114篇
  1990年   109篇
  1989年   106篇
  1988年   112篇
  1987年   107篇
  1986年   87篇
  1985年   102篇
  1984年   118篇
  1983年   97篇
  1982年   110篇
  1981年   117篇
  1980年   105篇
  1979年   102篇
  1978年   110篇
  1977年   89篇
  1976年   94篇
  1975年   65篇
  1974年   77篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
The present study examined the hypothesis that individuals are more influenced by a drug name than by the side effects associated with that drug when making recommendations regarding regulation. Subjects recommended the amount of regulation that should exist for eight drugs ranging from aspirin to LSD. One third of the subjects were asked to make recommendations based only on the drug name. Another third made recommendations based only on the facts associated with the drugs (i.e., side effects, symptoms). A final third made recommendations based on both facts and the drug name. Results indicated that, when given only the facts, subjects' recommendations deviated greatly from the actual regulation of the drugs but that the facts were ignored if subjects knew the name of the drug. These results suggest that critical information may be ignored when decisions are made about drug regulation. The implications for self-regulated drug use are discussed.  相似文献   
92.
Although meditation is increasingly being employed as an adjunct in psychotherapy, there has been practically no comprehensive evaluation of its usefulness in this respect. This paper seeks to address this issue through conceptual models of the meditation experience. It is concluded that meditation practice may be associated with the acquisition of some useful skills (e.g., focused attention), that practice may be physiologically relaxing, that meditation may decrease anxiety, insomnia and drug usage, while enhancing hypnotic induction and self-actualization. There is still no compelling evidence, however, that meditation practice is associated with unique state effects compared with other relaxational procedures. Those who appear to benefit most from meditation appear to be those who present with milder disorders. The clinical value of meditation, therefore, appears to be limited. Furthermore, the long-term objectives of meditation are not in general congruent with those of mainstream psychotherapy, as they go beyond therapeutic gain in the clinical sense.  相似文献   
93.
94.

Two experiments investigated the role of lithium-mediated environmental conditioning on instrumental performance. Experiment 1 demonstrated that a novel taste consumed in one arm of a T maze prior to lithium-induced toxicosis reduced performance in this environment whereas similar aversions conditioned in the home cage failed to alter maze performance. Experiment 2 showed that maze performance in a straight alleyway was decremented during extinction only in a group that actually traversed the alley prior to drinking saccharin and receiving lithium injections. This demonstrated that the instrumental decrement observed in Experiment 1 was due not only to the presence of an unpalatable flavor in the goalbox during the test.

  相似文献   
95.
Regional cerebral glucose metabolism in aphemia: A case report   总被引:1,自引:0,他引:1  
Local cerebral metabolism was determined in a patient suffering aphemia following cerebral infarction using the 18FDG-PET technique. The syndrome was characterized by profound ictal nonfluency with sparing of other language functions. Speech subsequently improved so that content and grammar were appropriate but mild dysprosody persisted. Conventional CT showed no lesion of the left hemisphere while PET revealed a discrete focus of hypometabolism on the left which partially resolved on serial studies. The metabolic lesion could be localized to the region of the inferior precentral gyrus and the adjacent subcortical space.  相似文献   
96.
Two experiments investigated the modulation of event-related potentials (ERPs) by the repetition of orthographically legal and illegal nonwords. In Experiment 1, subjects silently counted occasional words against a background of nonwords, a proportion of which were repetitions of an immediately preceding legal or illegal item. ERPs to repeated legal items showed a sustained, topographically diffuse, positive-going shift. In contrast, repeated illegal nonwords gave rise to ERPs showing a smaller and temporally more restricted positive-going modulation. In an attempt to equalize depth of processing across legal and illegal nonwords, subjects in Experiment 2 were required to count items containing a nonalphabetic character against the same background of nonword items. ERPs to repeated legal items showed a modulation similar to, although smaller than, that found in Experiment I, but no effects of repetition were observed in the ERPs to the illegal nonwords. It was concluded that the effects of repeating nonwords, at least as manifested in concurrently recorded ERPs, differ as a consequence of whether items can access lexical memory, and that this is inconsistent with the attribution of such effects solely to the operation of episodic memory processes.  相似文献   
97.
Two character-identification experiments investigated the function of structural context during the processing of briefly exposed algebraic strings. Neither experiment prodded evidence to support the notion of an algebra-superiority effect, a contextually driven enhancement of the recognition of specific algebraic characters. However, the results of Experiment 2 indicate that the structure of algebra does provide information at the level of a character’s categorical denomination. These findings suggest that the parsing of an algebraic string includes a level of processing in which its structural context places restrictions on the denominations of its symbols. A processing model of algebraic perception is proposed that incorporates these syntactic constraints—constraints that appear to be independent of feature-based character identification processes.  相似文献   
98.
The conclusions derived by Keynes in his Treatise on Probability (1921) concerning induction, analogical reasoning, expectations formation and decision making, mirror and foreshadow the main conclusions of cognitive science and psychology.The problem of weight is studied within an economic context by examining the role it played in Keynes' applied philosophy work, The General Theory (1936). Keynes' approach is then reformulated as an optimal control approach to dealing with changes in information evaluation over time. Based on this analysis the problem of inductive justification, from a societal perspective, is not, What can we rationally believe will occur in the economic future, given our past experiences? but Can we make the future so as to attain specific economic goals with practical certainty? An answer requires that restrictions be placed on the methodological individualist approach and the acceptance of a restricted holistic approach.  相似文献   
99.
Psychotropic drug treatment in learning-disabled (LD), educable mentally retarded (EMR), and seriously emotionally disturbed (ED) children and adolescents receiving public school special education services was examined. The findings indicated that while treatment prevalence rates for EMR and ED groups were comparable, the rate for LD students was much lower. In the LD sample, pharmacotherapy was associated with higher ratings of behavioral deviance, longer placement in special education, less social integration, and greater peer rejection, which suggests that symptom severity is an important determiner of pharmacotherapy in this population.  相似文献   
100.
Subjects making lexical decisions are reliably faster in responding to high-frequency words than to low-frequency words. This is known as the word frequency effect. We wished to demonstrate that some portion of this effect was due to frequency differences between words rather than to other dimensions correlated with word frequency. Three groups of subjects (10 engineers, 10 nurses, and I0 law students) made lexical decisions about 720 items, half words and half nonwords, from six different categories (engineering, medical, low-frequency nontechnical, medium-frequency nontechnical, and two groups of high-frequency nontechnical). Results of two analyses of variance revealed a crossover interaction such that engineers were faster in responding to engineering words than to medical words, whereas nurses were faster in responding to medical words than to engineering words. The engineering and medical words were equally long and equally infrequent by standard word counts. We take this as support for a frequency-based component in the word frequency effect. The practical implications of this research for estimating the readability of technical text 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