全文获取类型
收费全文 | 14560篇 |
免费 | 281篇 |
国内免费 | 191篇 |
专业分类
15032篇 |
出版年
2015年 | 37篇 |
2013年 | 37篇 |
2012年 | 1402篇 |
2011年 | 1587篇 |
2010年 | 374篇 |
2009年 | 203篇 |
2008年 | 1230篇 |
2007年 | 1179篇 |
2006年 | 1120篇 |
2005年 | 847篇 |
2004年 | 832篇 |
2003年 | 742篇 |
2002年 | 696篇 |
2001年 | 477篇 |
2000年 | 561篇 |
1999年 | 261篇 |
1998年 | 96篇 |
1997年 | 39篇 |
1996年 | 63篇 |
1995年 | 50篇 |
1994年 | 88篇 |
1993年 | 99篇 |
1992年 | 102篇 |
1991年 | 121篇 |
1990年 | 100篇 |
1989年 | 102篇 |
1988年 | 109篇 |
1987年 | 131篇 |
1986年 | 92篇 |
1985年 | 118篇 |
1984年 | 122篇 |
1983年 | 144篇 |
1982年 | 100篇 |
1981年 | 95篇 |
1980年 | 83篇 |
1979年 | 90篇 |
1978年 | 81篇 |
1966年 | 51篇 |
1965年 | 131篇 |
1964年 | 106篇 |
1963年 | 127篇 |
1962年 | 54篇 |
1958年 | 134篇 |
1957年 | 133篇 |
1956年 | 87篇 |
1955年 | 62篇 |
1954年 | 52篇 |
1953年 | 44篇 |
1952年 | 47篇 |
1951年 | 43篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
871.
Underemployment in America: Measurement and Evidence 总被引:4,自引:0,他引:4
An important way in which employment hardship has come to be conceptualized and measured is as underemployment. Underemployment goes beyond mere unemployment (being out of a job and looking for work), to include those who have given up looking for work, part-time workers whose employer(s) cannot give them full-time work, and the working poor. To provide needed background for the other articles in this special issue, we trace the history of the concept of underemployment, review existing empirical literature, offer a critique of the measurement of underemployment as conventionally operationalized, and provide up-to-date evidence on the trends and correlates of underemployment in the United States. 相似文献
872.
Wolraich ML Lambert EW Baumgaertel A Garcia-Tornel S Feurer ID Bickman L Doffing MA 《Journal of abnormal child psychology》2003,31(4):445-455
This study evaluates a measurement model for Attention Deficit/Hyperactivity Disorder (ADHD). The DSM-IV divides 18 symptoms into two groups, inattentive and hyperactive/impulsive. Elementary school teachers rated 21,161 children in 4 locations: Spain, Germany, urban US, and suburban US. Confirmatory factor analysis suggested that the 2-factor model (inattention, hyperactivity/impulsivity) shows the best fit. A third factor, impulsivity, was too slight to stand-alone. Children with academic performance problems were distinguished by inattention, but children with behavior problems typically had elevations in inattention, hyperactivity, and impulsivity. Between-site differences were statistically significant, but so small that we conclude that same measurement model fits all 4 samples in 2 continents. 相似文献
873.
Does the right hemisphere take over after damage to Broca's area? the Barlow case of 1877 and its history 总被引:3,自引:0,他引:3
In 1877 Thomas Barlow, a London physician, published a remarkable case of functional recovery of speech following brain damage. It involved a 10-year-old boy who had lost his speech, regained it, and lost it again before he died from a disorder that affected his heart and produced embolisms that subsequently affected other organs, including his brain. Examination of the boy's brain revealed two focal regions of softening; one that affected Broca's area and the left facial-motor area, and another, which occurred weeks later, in the homologous regions of the right hemisphere. Although Barlow was most concerned with motor deficits, others at the turn of the century began to cite this case as strong evidence that the corresponding region of the right hemisphere can take over speech functions for Broca's area on the left. Whether this case really provides good support for functional takeover or vicariation theory is critically evaluated in the light of contemporary research, including PET scan studies involving damage to Broca's speech region. 相似文献
874.
Different types of syntactic information (word category, grammatical gender) are processed at different times during word recognition. However, it is an open issue which brain systems support these processes. In the present event-related fMRI study, subjects performed either a syntactic gender decision task on German nouns (GEN), a word category decision task (WC, nouns vs. prepositions), or a physical baseline task (BASE). Reaction times in WC were faster than in GEN, supporting earlier electrophysiological results. Relative to BASE, both syntactic tasks activated the inferior tip of BA 44. In addition, BA 45 showed activation in GEN, whereas BA 47 was activated in WC. The imaging data indicate that the inferior portion of BA 44 together with type-specific prefrontal areas supports both initial word category related and later syntactic processes. 相似文献
875.
Weak coherence,no theory of mind,or executive dysfunction? Solving the puzzle of pragmatic language disorders 总被引:4,自引:0,他引:4
Deficits in pragmatic language ability are common to a number of clinical populations, for example, right-hemisphere damage (RHD), Autism and traumatic brain injury (TBI). In these individuals the basic structural components of language may be intact, but the ability to use language to engage socially is impaired. Despite the nature of these difficulties being well documented, exactly what causes these difficulties is less clear. Furthermore, the current status of causal explanations for pragmatic difficulties across these populations is divergent and sometimes contradictory. This paper explores the empirical validity of three theories that attempt to explain pragmatic language impairment. It is recommended that a new, more convergent approach to investigating the causes of pragmatic language disability be adopted. 相似文献
876.
Taylor J Loney BR Bobadilla L Iacono WG McGue M 《Journal of abnormal child psychology》2003,31(6):633-645
Psychopathy appears to be comprised of two broad dimensions: impulsivity/antisocial behavior and interpersonal detachment/callousness. This study examined the extent to which variance in these 2 psychopathy trait dimensions was associated with common or unique genetic, shared, and nonshared environmental factors in two independent samples of reared together 16–18-year-old male twins. One sample included 142 monozygotic (MZ) and 70 dizygotic (DZ) pairs; the other sample included 128 MZ and 58 DZ pairs. Boys completed the Minnesota Temperament Inventory (MTI), a 19-item measure that contains separate subscales: Antisocial and Detachment. Variance in the Antisocial and Detachment scales was associated with additive genetic factors and neither scale was associated with shared environmental factors. As expected, the bivariate biometric analysis suggested genetic influence on the covariance of the scales. The results are consistent with theoretical models of psychopathy that posit some independence in the etiology of the two major trait dimensions of psychopathy. 相似文献
877.
Temporal integration of speech prosody is shaped by language experience: an fMRI study 总被引:5,自引:0,他引:5
Gandour J Dzemidzic M Wong D Lowe M Tong Y Hsieh L Satthamnuwong N Lurito J 《Brain and language》2003,84(3):318-336
Differences in hemispheric functions underlying speech perception may be related to the size of temporal integration windows over which prosodic features (e.g., pitch) span in the speech signal. Chinese tone and intonation, both signaled by variations in pitch contours, span over shorter (local) and longer (global) temporal domains, respectively. This cross-linguistic (Chinese and English) study uses functional magnetic resonance imaging to show that pitch contours associated with tones are processed in the left hemisphere by Chinese listeners only, whereas pitch contours associated with intonation are processed predominantly in the right hemisphere. These findings argue against the view that all aspects of speech prosody are lateralized to the right hemisphere, and promote the idea that varying-sized temporal integration windows reflect a neurobiological adaptation to meet the 'prosodic needs' of a particular language. 相似文献
878.
We examined the morphosyntax of eight left hemispherectomized children at two different stages and compared it to MLU-matched normals. We found that the language of the hemispherectomies paralleled that of their MLU matches with respect to the specific morphosyntactic characteristics of each stage. Our findings provide strong evidence for the presence of functional categories in all early grammars and demonstrate that grammatical development, regardless of its neural substrate, is highly constrained by UG and follows a narrowly determined course. We discuss our findings within a neurobiological framework in which etiology defines the integrity of the remaining hemisphere, which in turn, determines its potential for linguistic reorganization and/or acquisition. 相似文献
879.
Campbell L Simpson JA Stewart M Manning J 《Personality & social psychology bulletin》2003,29(12):1547-1559
The present research tested relations between extraversion and emergent leadership among men in situations that differed in potential reward availability. Four-person groups of men engaged in a Leaderless Group Discussion (LGD) task and were randomly assigned to be evaluated by an attractive female observer, an attractive male observer, or not be evaluated. Evolutionary theories suggest that impressing a female evaluator in an intrasexually competitive situation should hold greater reward potential for men than impressing either a male evaluator or no evaluator. Accordingly, more extraverted men (who are more sensitive to reward cues) should display more group leadership when being evaluated by a woman than either a man or no one. Self-and peer ratings confirmed that more extraverted men were significantly more likely to emerge as leaders, but only in the female-evaluator condition. The results are discussed in terms of the interplay between personality, situational factors, and evolutionary principles. 相似文献
880.
Johnson JD Simmons C Trawalter S Ferguson T Reed W 《Personality & social psychology bulletin》2003,29(5):609-622
Experiment 1 indicated that when the White supervisor's negative treatment of a Black subordinate was unconstrained, participant race had no impact on attributions. Conversely, when the treatment was constrained, Black participants reported greater racist attributions than did White participants. Experiment 2 indicated that when the supervisor reported no response or a minimal negative response (i.e., indicating that he did not support his actions) after his negative treatment of the Black subordinate, Black participants reported greater racist attributions than did White participants. Conversely, when the supervisor's negative treatment was followed by a more extreme negative response, participant race had no impact on attributions. Experiment 3 indicated that Black participants were less likely than White participants to perceive a minimal negative response as reflecting a White supervisor's lack of support for his negative actions. Conversely, participant race had no impact on attributions of a Black supervisor's negative actions. 相似文献