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   22478篇
  免费   856篇
  国内免费   16篇
  2020年   242篇
  2019年   269篇
  2018年   495篇
  2017年   479篇
  2016年   570篇
  2015年   395篇
  2014年   360篇
  2013年   1524篇
  2012年   852篇
  2011年   944篇
  2010年   415篇
  2009年   408篇
  2008年   558篇
  2007年   538篇
  2006年   487篇
  2005年   1652篇
  2004年   1021篇
  2003年   778篇
  2002年   499篇
  2001年   746篇
  2000年   728篇
  1999年   514篇
  1998年   210篇
  1997年   202篇
  1996年   158篇
  1995年   160篇
  1993年   163篇
  1992年   398篇
  1991年   382篇
  1990年   408篇
  1989年   393篇
  1988年   350篇
  1987年   332篇
  1986年   361篇
  1985年   340篇
  1984年   275篇
  1983年   232篇
  1979年   229篇
  1978年   174篇
  1977年   150篇
  1975年   215篇
  1974年   279篇
  1973年   228篇
  1972年   226篇
  1971年   184篇
  1970年   171篇
  1969年   215篇
  1968年   219篇
  1967年   178篇
  1966年   198篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
911.
Contemporary findings reveal that the multiple modes of autonomic control do not lie along a single continuum extending from parasympathetic to sympathetic dominance but rather distribute within a 2-dimensional space. The physiological origins and empirical documentation for the multiple modes of autonomic control are considered. Then a formal 2-dimensional conception of autonomic space is proposed, and a quantitative model for its translation into a functional output surface is derived. It is shown that this model (a) accounts for much of the error variance that has traditionally plagued psychophysiological studies, (b) subsumes psychophysiological principles such as the law of initial values, (c) gives rise to formal laws of autonomic constraint, and (d) has fundamental implications for the direction and interpretation of a wide array of psychophysiological studies.  相似文献   
912.
A previous study (Tr?ster, 1989) showed that nonhandicapped persons preferred a physically handicapped interaction partner to a nonhandicapped partner in an attributionally unambiguous situation. In order to test whether this "sympathy effect of physical handicap" is based on tendencies of impression management, 48 female subjects had to choose to sit next to either a physically handicapped or nonhandicapped female interaction partner in order to view a film together. Attributional ambiguity was varied by either confounding the choice of an interaction partner with a second, socially acceptable alternative (attributionally ambiguous situation: a choice between two films) or not confounding it (attributionally unambiguous situation: no choice between films). Public responsibility was manipulated by informing the subjects about their freedom to choose where they wished to sit either in public (public responsibility) or in private (no public responsibility). The results supported the impression management hypothesis: The handicapped interaction partner (in a wheelchair) was only preferred when the subjects had to anticipate that observers would deduce a preference of the chosen partner from the subjects' choices because of the attributionally unambiguous situation and the public announcement of their freedom of choice. Results suggest that the nonhandicapped strive to exhibit positive and nondiscriminative behavior toward the handicapped in order to avoid creating a disadvantageous impression in an observer.  相似文献   
913.
We investigate the effects of emotional mood states on solving simple pattern comparison tasks. It is assumed that the effects of mood are mediated through response biases as well as effort expenditure. Departing from these assumptions, trend hypotheses are derived for the response biases evaluated by means of a signal detection analysis, for the response latencies, and for an adequate index of the underlying ability. The data support the hypotheses, and in particular, a positive mood state is found to improve performance. The assumption of mood-dependent differences in effort expenditure provides a parsimonious and integrative account of our results, while a reduced-capacity view cannot explain the findings obtained under positive mood induction.  相似文献   
914.
Examined postpartum effects of a school-based intervention program for pregnant adolescents. Interviews were conducted with 102 innercity black, low-income, school-aged mothers who had attended the program, and their academic and medical records were reviewed. For teenagers who had been poor students prior to becoming pregnant, a strong linear effect was found for duration of program attendance: with sufficient time in the program, poorer students became indistinguishable from better students in educational success. Most of the better students were educationally successful at 2 years postpartum, independent of their length of time in the program. For all students, longer durations of postnatal intervention were predictive of lower likelihood of subsequent childbearing. Numerous academic, medical, social, and demographic variables were ruled out as possible confounding factors that might have produced the positive educational outcomes for poorer students. The results suggest that adolescents who appear to have minimal academic promise prior to their pregnancy are nevertheless very responsive to school-based intervention.  相似文献   
915.
There appear to be beneficial effects of stimulant medication on daily classroom measures of cognitive functioning for Attention Deficit Disorder (ADD) children, but the specificity and origin of such effects is unclear. Consistent with previous results, 0.3 mg/kg methylphenidate improved ADD children's performance on a classroom reading comprehension measure. Using the Posner letting-matching task and four additional measures of phonological processing, we attempted to isolate the effects of methylphenidate to parameter estimates of (a) selective attention, (b) the basic cognitive process of retrieving name codes from permanent memory, and (c) a constant term that represented nonspecific aspects of information processing. Responses to the letter-matching stimuli were faster and more accurate with medication compared to placebo. The improvement in performance was isolated to the parameter estimate that reflected nonspecific aspects of information processing. A lack of medication effect on the other measures of phonological processing supported the Posner task findings in indicating that methylphenidate appears to exert beneficial effects on academic processing through general rather than specific aspects of information processing.  相似文献   
916.
We investigated the effects of background anger, provocation, and methylphenidate on emotional, physiological, and behavioral responding in children with attentiondeficit hyperactivity disorder (ADHD) with and without concurrent aggression. Our study revealed that ADHD boys showed more emotional and physiological distress when exposed to an interaction in which an administrator chastised each boy's favorite counselor, compared to a friendly interaction between the two adults. The background anger manipulation did not affect the aggressive behavior of the boys against an opponent in an aggressive game. High-aggressive (HA) ADHD boys were more likely to respond to provocation with aggression than low-aggressive (LA) ADHD boys, but only LA boys showed increased physiological reactivity with increasing provocation. Methylphenidate resulted in increased heart rates under all conditions and did not interact with any of the other findings.This project was conducted while the first author had the support of National Institute of Alcohol Abuse and Alcoholism grant AA 06267.The authors wish to thank the staff members of the 1987 Summer Day Treatment Program who assisted in conducting this project. The authors also express their appreciation to Karen Guthrie for coordinating the medication assessment and to Hart Blanton for computer programming.  相似文献   
917.
Early lexical development in children with focal brain injury   总被引:4,自引:0,他引:4  
Early lexical development in 27 children with focal brain injury was studied cross-sectionally and longitudinally. Data were obtained from children between 12 and 35 months of age who acquired their lesion prenatally or within the first 6 months of life. Results for the group as a whole provide clear evidence for delays in lexical comprehension and production, and for a larger number of comprehension/production dissociations than would be expected by chance. In addition, a significant number of children were observed having unusual difficulty mastering predication and/or using an atypically high proportion of closed class words (suggesting reliance on holistic/formulaic speech). Analyses by lesion type revealed no effect of lesion size. Analyses according to side of lesion revealed that children with right-hemisphere damage produced a higher proportion of closed class words, suggesting heavy reliance on well-practiced but under-analyzed speech formulae. Children with left-hemisphere damage were slightly better in comprehension than children with right-hemisphere damage. In addition, left posterior lesions were associated with greater delays in expressive language, and delays were more protracted in children with left posterior damage. No differential effects of left posterior damage were found for lexical comprehension.  相似文献   
918.
Results of auditory speech experiments show that reaction times (RTs) for place classification in a test condition in which stimuli vary along the dimensions of both place and voicing are longer than RTs in a control condition in which stimuli vary only in place. Similar results are obtained when subjects are asked to classify the stimuli along the voicing dimension. By taking advantage of the "McGurk" effect (McGurk & MacDonald, 1976), the present study investigated whether a similar pattern of interference extends to situations in which variation along the place dimension occurs in the visual modality. The results showed that RTs for classifying phonetic features in the test condition were significantly longer than in the control condition for the place and voicing dimensions. These results indicate a mutual and symmetric interference exists in the classification of the two dimensions, even when the variation along the dimensions occurs in separate modalities.  相似文献   
919.
The traditional clinical picture for English nonfluent aphasics has generally presented the deficit as one of total loss of control over grammatical morphology, with some sparing of word order. This is at odds with recent research involving nonfluent aphasic speakers of highly inflected languages, which has shown that agrammatic performance is characterized by morphological substitution rather than omission errors. If the deficit associated with focal brain damage cannot be adequately accounted for in syndrome-specific ways, we may need to look for language-specific processing explanations. One such explanation has to do with language-specific response to global processing difficulty. The current experiment is designed to study the effects of a stress-related limitation on morphological processing. Normal speakers of a language with a relatively rich morphological system (German) are compared with those of a comparatively impoverished system (English) on different forms of a sentence comprehension task. In one form, "clean" stimuli permit full reliance on all available cues to meaning in each language. In another test, a low-level noise mask partially obscured the stimulus sentences. English speakers, who rely almost exclusively on word order cues, were not affected by the noise manipulation. German speakers relied heavily on morphological and semantic information rather than on word order under "clean" conditions. However, under noise Germans made significantly less use of grammatical morphology, with a trend toward compensatory reliance on word order. The results indicate that a global reduction in processing capacity can affect some aspects of language more than others and suggest that such factors must be taken into account in trying to understand specific impairment of morphology in aphasia.  相似文献   
920.
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