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   22149篇
  免费   134篇
  2023年   16篇
  2022年   12篇
  2021年   16篇
  2020年   45篇
  2019年   62篇
  2018年   3523篇
  2017年   2871篇
  2016年   2313篇
  2015年   239篇
  2014年   143篇
  2013年   309篇
  2012年   673篇
  2011年   2474篇
  2010年   2556篇
  2009年   1526篇
  2008年   1773篇
  2007年   2233篇
  2006年   105篇
  2005年   264篇
  2004年   240篇
  2003年   163篇
  2002年   114篇
  2001年   61篇
  2000年   76篇
  1999年   40篇
  1998年   44篇
  1997年   35篇
  1996年   22篇
  1995年   22篇
  1994年   12篇
  1993年   14篇
  1992年   14篇
  1991年   15篇
  1990年   21篇
  1989年   13篇
  1988年   11篇
  1986年   11篇
  1985年   12篇
  1984年   17篇
  1983年   11篇
  1981年   8篇
  1980年   12篇
  1979年   14篇
  1978年   15篇
  1975年   15篇
  1973年   14篇
  1972年   8篇
  1971年   8篇
  1969年   8篇
  1968年   11篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
present research examined the role of hippocampal NMDA-dependent synaptic potentiation on appetitive instrumental conditioning under a continuous reinforcement schedule. In the first experiment, low (.025 mg.kg) or moderate (.05 mg/kg) dosages of the NMDA receptor antagonist, MK801, failed to increase the number of training days required to reach acquisition criterion; number of training days required to reach criterion for extinction were also unaffected. In the second experiment, a higher dosage (.10 mg/kg) of MK801 or induction of long-term potentiation failed to alter the number of responses occurring during acquisition. These data suggest that hippocampal synaptic potentiation does not play a prominent role in instrumental learning with simple contingency conditions. It is suggested that hippocampal LTP reflects a perceptual process that contributes differentially to spatial cognition, classical and instrumental conditioning.  相似文献   
42.
Although choices of required textbooks are important decisions in developing a course curriculum, faculty in marriage and family therapy training programs have few convenient resources to guide curriculum development. This article presents results of a survey of textbook selections of accredited marriage and family therapy programs within a regional affiliate of AAMFT. The five programs surveyed listed 108 different titles used in their curriculum. Only 12 texts were used by two programs, and only one text was used by more than two programs. This article presents the textbook selections by the six curricular areas of COAMFTE accreditation standards. The wide variety of textbooks used by programs leads us to conclude that no consensus exists about what textbooks best represent the core knowledge of marriage and family therapy. The body of knowledge taught in accredited marriage and family training programs reflects a distinct and autonomous body of knowledge.  相似文献   
43.
Abstract— Semantically associated and unassociated word pairs were embedded in normal meaningful sentences and in sentences that were semantically anomalous throughout The influence of lexical context was isolated via comparison of responses to the second words of the associated and unassociated pairs. The influence of sentence-level context was isolated by comparing responses to the same words in the two sentence types Subjects of high, medium and low working memory capacity (as evaluated by the reading span test) showed modulations of event-related brain potentials in response so lexical context. In contrast, only the high- and medium-capacity groups were responsive to purely sentence-level semantic context. The results demonstrate that sentential context influences the processing of words in intermediate sentence positions at normal reading speeds but that the on-line utilization of this context is more demanding of working memory than single-word contexts.  相似文献   
44.
45.
How can we explain that an assertion on something perceived can be understood in the same manner by somebody who cannot perceive that scene? This problem bases the interest in computational linguistics in how listener modeling could possibly be harmonized with reference semantics. Mental images substituting real perception appear as a way out. The architecture of the listener model has to be adapted to the creation and use of such pictorial data structures. Furthermore, the relation between the latter and a verbal (i. e., propositional) representation must be understood. The resulting architecture of a listener model with reference semantics can be employed to solve communicational problems from three general classes in a better way, as is demonstrated by an example implementation.  相似文献   
46.
Recent work has sought to use the time at which the Lateralized Readiness Potential (LRP) first develops (LRP onset) as a temporal landmark to bisect experimental effects on reaction time (RT). Many studies have found experimental effects on the time between the signal and LRP onset, but few have found effects on the time between LRP onset and RT (LRP-RT interval). The primary goal of this study was to produce an effect on the LRP-RT interval. We employed precuing, a manipulation likely to influence motor-programming processes at the end of the RT interval. Subjects performed a 4-alternative choice-RT task in which a signal prompted a button-press with the index or middle finger on the left or right hand. Precues preceded the signals and were either informative, reducing the set of response alternatives from four to two, or uninformative. Besides RT and LRP, we also measured electromyographic (EMG) activity and the P300 ERP component. RT, P300 latency, and the interval between the signal and LRP onset were all shorter with informative than uninformative precues, but the timing of EMG activity relative to RT remained the same. Most importantly, precuing affected the LRP-RT interval. Implications for bisecting RT with LRPs and the identity of processes affected by precuing are discussed.  相似文献   
47.
Media reports suggest that the public is becoming impatient with the homeless—that so-called “compassion fatigue” has gripped the nation. This characterization of public sentiment could have important policy consequences—restrictive measures can be justified by growing public impatience, and progressive housing policies seem infeasible within a hostile climate of opinion. But evidence to support the compassion fatigue notion is anecdotal. We examine the issue by tracking the results of public opinion polls and by reporting detailed evidence from a nationwide random-digit dial telephone survey (N=1,507) concerning knowledge attitudes and beliefs about homeless people. To be sure, the public sees homelessness as an undesirable social problem and wants something done about it. However, although the homeless are clearly stigmatized, there is little evidence to suggest that the public has lost compassion and is unwilling to support policies to help homeless people.  相似文献   
48.
Over the past decade, sport participation opportunities for females have increased dramatically. The purposes of this study were to compare perceptions of encouragement and support from socializing agents for: (a) female collegiate volleyball players competing during the 1979 and 1989 seasons, and (b) female collegiate athletes and female and male nonathletes. Female athletes (n= 345), female nonathletes (n= 128), and male nonathletes (n= 88) completed a questionnaire to assess significant others' influence on sport involvement during childhood, adolescence, and college years. Results indicated that interest and encouragement by parents, older siblings, and friends significantly increased for female athletes over the past 10 years during one or more developmental period. Discriminant analyses revealed that female athletes perceived stronger influences from mother, siblings, friends, and coaches than did male and female nonathletes. These results demonstrate that female athletes received greater social support than their peers a decade earlier, and these influences were significantly different than male and female nonathletes. This study was supported by a grant awarded to the first author by the Center for the Study of Women in Society, University of Oregon, Eugene.  相似文献   
49.
Abstract— Fourteen-year-old adolescents' behavior on a spatial-visual reasoning task was associated with self-report of their mothers' alcohol consumption during pregnancy, IS years earlier The task was arranged so that it was possible to evaluate the examinees' tendency to respond rapidly and less accurately, or slowly and more accurately The greater the mother's reported drinking, the faster and less accurately the adolescent responded The decrement in visual-spatial reasoning related to alcohol appears to be linked to a tendency toward impulsive responding  相似文献   
50.
Heather A. Turner 《Sex roles》1994,30(7-8):521-541
In examining past research, a paradox can be found in the relationships between gender, social support, and depression. Although women report higher levels of depression than men, they also generally report more social support—a factor found to reduce depressive symptoms. In efforts to explain this seeming inconsistency, it was hypothesized that women report both more support and more depression because they are more likely than men to experience both positive and negative aspects of social relationships. Based on a community sample of predominantly Caucasian respondents, findings indicate that greater perceived support among women can be explained by more frequent contact with network members and a tendency to possess relationships characterized by greater intimacy, emotional disclosure, and empathy. However, women also report more frequent negative interactions with network members and are more adversely affected by marital conflict than are men. While negative interactions and conflict cannot account for gender differences in depression, they do help to explain how women can experience both more support and more depression. Among women, the health-enhancing effects of support on depression may be balanced by the detrimental effect of conflict.  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