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   66018篇
  免费   2726篇
  国内免费   45篇
  2020年   773篇
  2019年   935篇
  2018年   1348篇
  2017年   1352篇
  2016年   1419篇
  2015年   983篇
  2014年   1162篇
  2013年   5656篇
  2012年   2110篇
  2011年   2330篇
  2010年   1377篇
  2009年   1357篇
  2008年   2020篇
  2007年   1993篇
  2006年   1735篇
  2005年   1577篇
  2004年   1550篇
  2003年   1427篇
  2002年   1446篇
  2001年   2252篇
  2000年   2160篇
  1999年   1581篇
  1998年   814篇
  1997年   706篇
  1996年   630篇
  1995年   631篇
  1994年   596篇
  1993年   623篇
  1992年   1278篇
  1991年   1205篇
  1990年   1210篇
  1989年   1102篇
  1988年   1067篇
  1987年   1035篇
  1986年   1055篇
  1985年   1098篇
  1984年   855篇
  1983年   745篇
  1982年   572篇
  1979年   819篇
  1978年   624篇
  1975年   744篇
  1974年   824篇
  1973年   764篇
  1972年   711篇
  1971年   630篇
  1969年   612篇
  1968年   718篇
  1967年   681篇
  1966年   628篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
This study examines the effect of different behavioral conditions on patterns of correlation between regional cerebral metabolic rates for glucose. Cerebral glucose metabolism was determined with positron emission tomography and (11C)-deoxyglucose in 29 normal subjects between the ages of 23 and 55. Seventeen subjects were studied in an unstimulated (resting) condition and 12 subjects during a phoneme monitoring language stimulation. Partial correlation coefficients, controlling for whole brain glucose metabolism, were calculated for pairs of metabolic rates in 14 cortical and 2 subcortical regions. Both stimulated and unstimulated subjects showed statistically significant correlations between left and right hemisphere homologs. The stimulated subjects also showed significant within-hemisphere correlations between left but not right hemisphere regions. These included left perisylvian regions classically associated with language functions (left inferior frontal, left superior temporal and left transverse temporal cortical regions) as well as other regions. Significant correlations between left regions and a right superior temporal region were also found. In general, these findings show a pattern of cross-hemisphere symmetry at rest and of hemisphere asymmetry during stimulation. Moreover, the asymmetry observed during stimulation appears to be superimposed upon a pattern of cross-hemisphere symmetry similar to that observed in the unstimulated state.  相似文献   
952.
953.
Two left-handed siblings with developmental stuttering are comprehensively described. The methods of study included speech and language evaluation, neurological and neuropsychological examinations, dichotic listening, auditory evoked responses, electroencephalogram, and CT scan asymmetry measurements. The data from each sibling showed evidence of anomalous cerebral dominance on many of the variables investigated. The CT scan measurements showed atypical asymmetries, especially in the occipital regions. These findings support the theory that stuttering may be related to anomalous cerebral dominance, both on functional as well as structural bases. Implications of anomalous dominance and the resultant effect of hemispheric rivalry on speech fluency are discussed.  相似文献   
954.
At the work site, smoking accounts for increased health care expenses and worker absenteeism due to smoking-related illness and reduced productivity and lost wages. Developing comprehensive and accessible smoking cessation programs at the work site is an important objective for health care professionals. In this study, employees of 43 corporations participated in a televised smoking cessation program accompanied by self-help manuals. The media component involved presenting a smoking cessation program on a network television affiliate station during the 4:30 p.m. and 10:00 p.m. news for 20 days. Employees at half the corporations also had access to semiweekly self-help group meetings. Adding self-help support groups to a program involving self-help manuals and the media reports was found to significantly increase abstinence and its maintenance over time. The implications of using the media, self-help groups, and work site locations in large-scale community-based interventions are discussed.  相似文献   
955.
956.
There is given the proof of strict embedding of Leniewski's elementary ontology into monadic second-order calculus of predicates providing a formalization of the class of all formulas valid in all domains (including the empty one). The elementary ontology with the axiom S (S S) is strictly embeddable into monadic second-order calculus of predicates which provides a formalization of the classes of all formulas valid in all non-empty domains.  相似文献   
957.
Common formulations of the principle of charity in translation seem to undermine attributions of irrationality in social scientific accounts that are otherwise unexceptionable. This I call the problem of irrationality. Here I resolve the problem of irrationality by developing two complementary views of the principle of charity. First, I develop the view (ill-developed in the literature at present) that the principle of charity is preparatory, being needed in the construction of provisional first-approximation translation manuals. These serve as the basis for explanatory accounts and associated refinements in the translation manual. In developing such explanatory accounts, the principle of charity is no longer constraining. Thus, the principle of charity applies only in the early stages of constructing translation manuals, and there is no problem of irrationality in the later stages of constructing translation manuals. Second, I reduce the principle of charity, where it does apply, to a special case of what I call the principle of explicability: so translate as to attribute explicable beliefs and practices to the speakers of the source-language. I show that the appropriate formulation of the principle of charity counsels just what the principle of explicability requires in the early stages of social scientific investigation.I am grateful to Robert Barrett, Roger Gibson, and Paul Roth for their generous assistance.  相似文献   
958.
The course of bargaining is determined in part by interdependent individuals exchanging messages so as to influence other's behaviour, and thereby to increase the likelihood of achieving outcomes consistent with their own goals. The communication of threats and promises are two major message strategies that are employed to influence the behaviour of others in a bargaining relationship. The present study examines the effects of players' level of commitment to these forms of message strategies upon behaviour in a duopoly bargaining task. Past research has oprationalized commitment in terms of the consistency with which an individual has followed through on threats or promises in the past. In the present research, Becker's (1960) concept of a side-bet is employed to provide an alternative means for defining and manipulating commitment. A side-bet obtains when either a threatener or a promiser posts a valued resource, say a bond, which they forfeit if they do not follow through on their stated threat or promise. The main expectations of the present study were that increased commitment to threat meassages would lead to more competitive behaviour and outcomes within a duopoly bargaining task, whereas increased commitment to promise messages would produce more cooperative behaviour and outcomes. Partial support for these major expectations, as well as confirmation of a number of secondary expectations, was obtained.  相似文献   
959.
In this study, verbal memory and naming abilities were investigated in reading disabled (RD) and control children who were characterized according to the presence or absence of attention deficit disorder (ADD). Results indicate that deficits in learning and memory for recently acquired information occur as a function of ADD rather than RD while deficits in naming are specific to RD rather than ADD. We conclude that ADD is a major source of additional and separate cognitive morbidity in RD children.  相似文献   
960.
This paper presents the results of a study of active/passive sentence comprehension by a Polish-speaking agrammatic aphasic. The patient showed good performance on canonically ordered active and passive structures, but performed poorly on inverted variants. The systematically normal and deviant comprehension patterns observed are accounted for by normal interpretative strategies applied to syntactic structures built around verbs with reduced inflectional morphology. The differences between our Polish data and the English data discussed in the literature are explained by the fact that Polish possesses a richer derivational verb morphology. The interpretation of inverted sentences demonstrates the importance of S-V-O word order preference. Our analysis draws upon the notion of grammatical functions to explain the data.  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