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   13988篇
  免费   639篇
  国内免费   7篇
  2021年   101篇
  2020年   191篇
  2019年   221篇
  2018年   307篇
  2017年   356篇
  2016年   380篇
  2015年   277篇
  2014年   312篇
  2013年   1501篇
  2012年   566篇
  2011年   599篇
  2010年   378篇
  2009年   426篇
  2008年   540篇
  2007年   591篇
  2006年   510篇
  2005年   485篇
  2004年   468篇
  2003年   498篇
  2002年   476篇
  2001年   209篇
  2000年   216篇
  1999年   234篇
  1998年   192篇
  1997年   198篇
  1996年   200篇
  1995年   209篇
  1994年   173篇
  1993年   174篇
  1992年   181篇
  1991年   150篇
  1990年   127篇
  1989年   127篇
  1988年   132篇
  1987年   137篇
  1986年   126篇
  1985年   150篇
  1984年   172篇
  1983年   169篇
  1982年   179篇
  1981年   171篇
  1980年   160篇
  1979年   158篇
  1978年   158篇
  1977年   172篇
  1976年   158篇
  1975年   137篇
  1974年   131篇
  1973年   130篇
  1972年   92篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
981.
The present study was designed to examine the role that attentional problems may play in accounting for difficulties in story comprehension experienced by children with ADHD. A secondary task methodology was used to examine whether or not online variations in cognitive engagement with a televised story were related to the continuity of central or incidental information. Twenty-two 9- to 11 -year-old boys with ADHD and 36 of their nonreferred peers watched a television program and responded to auditory probes presented at preselected points during continuous sequences of central or incidental information. The reaction times to the probes for nonreferred boys showed the expected linear increase in cognitive engagement (i.e., the RTs increased) as central, plot-relevant sequences continued. In contrast, boys with ADHD showed the expected increase in RTs relatively late in the central sequences. The results were discussed in terms of how delays in engaging with central information may contribute to the academic difficulties experienced by boys with ADHD.  相似文献   
982.
Recent research has indicated that the pro-inflammatory cytokines, particularly interleukin-1beta (IL-1beta), can affect learning and memory. We injected male Sprague-Dawley rats with IL-1beta (1.0, 3.0, or 6.0 microg/kg, i.p.) or saline vehicle, 24h before a single 4-h session of leverpress escape/avoidance conditioning. No effect of IL-1beta at any dose was observed in the number of escape responses across the 4-h session. However, subjects treated with the two lower doses (1.0 and 3.0 microg/kg) of IL-1beta performed more avoidance responses during the final hour of the 4-h session than the other two groups. Subjects treated with the highest dose of IL-1beta (6.0 microg/kg) did not differ from controls. Results are discussed in terms of the possible mechanisms behind the IL-1beta-induced enhancement of learning, as well as the observed dose-response relationship.  相似文献   
983.
The present paper examines the role of cognitive-behavioral therapy (CBT) in the treatment of social anxiety disorder (SAD). A cognitive-behavioral model of SAD is first presented. Different modalities of CBT for SAD are then described, including exposure, cognitive restructuring, relaxation training, and social skills training, and evidence supporting their efficacy is reviewed. The comparative and combined impact of CBT and pharmacotherapeutic interventions is also explored. CBT appears to be an efficacious treatment for SAD. However, the overall efficacy CBT may be increased by closer examination of the active ingredients of treatment. Such analyses may also enable more successful integration of the different CBT techniques and of CBT and pharmacotherapy in the treatment of SAD.  相似文献   
984.
985.
Neuroimaging and computational modeling studies have led to the suggestion that response conflict monitoring by the anterior cingulate cortex plays a key role in cognitive control. For example, response conflict is high when a response must be withheld (no-go) in contexts in which there is a prepotent tendency to make an overt (go) response. An event-related brain potential (ERP) component, the N2, is more pronounced on no-go than on go trials and was previously thought to reflect the need to inhibit the go response. However, the N2 may instead reflect the high degree of response conflict on no-go trials. If so, an N2 should also be apparent when subjects make a go response in conditions in which nogo events are more common. To test this hypothesis, we collected high-density ERP data from subjects performing a go/no-go task, in which the relative frequency of go versus no-go stimuli was varied. Consistent with our hypothesis, an N2 was apparent on both go and no-go trials and showed the properties expected of an ERP measure of conflict detection on correct trials: (1) It was enhanced for low-frequency stimuli, irrespective of whether these stimuli were associated with generating or suppressing a response, and (2) it was localized to the anterior cingulate cortex. This suggests that previous conceptions of the no-go N2 as indexing response inhibition may be in need of revision. Instead, the results are consistent with the view that the N2 in go/no-go tasks reflects conflict arising from competition between the execution and the inhibition of a single response.  相似文献   
986.
The nature of the association between anger and 5 appraisal-action tendency components--goal obstacle, other accountability, unfairness, control, and antagonism--was examined in terms of specificity, necessity, and sufficiency. In 2 studies, participants described recently experienced unpleasant situations in which 1 of the appraisal-action tendency components was present or absent and indicated which emotions they had experienced. The results showed that (a) other accountability and arrogant entitlement, as an instance of unfairness, are specific appraisals ability for anger; and most important, (b) none of the components is necessary or sufficient for anger. The findings suggest that the relation between emotions and appraisal-action tendency components should be conceptualized instead as a contingent association, meaning that they usually co-occur.  相似文献   
987.
988.
A novel type of locomotion compensator was designed and tested for its use in orientation behavior experiments with a predatory mite. In this apparatus, displacements of the test animal in the two-dimensional plane are recorded using video equipment and a servosphere that keeps the animal in focus. Thex andy displacements are registeredusing two rotation encoders and are compensated using a pair of servo-motors, in such a way that the animal is always positioned on top of the sphere, yet moves freely. Well-fed and starved predators were tested for their responses to (1) still air, (2) a stimulus-free air flow, (3) an air flow with odors from uninfested Lima bean leaves, and (4) an air flow with odors from Lima bean leaves infested by plant-feeding mites, the prey of the predatory mites. Anemotactic responses of adultPhytoseivlus persimilis females were feeding state dependent. Well-fed predators moved downwind under Treatments 1–3 but moved neither up-nor downwind in the presence of odors from infested plants (Treatment 4). Starved predators moved upwind under all treatments. These results are in agreement with those of earlier studies in a wind tunnel, and therefore, the new type of locomotion compensator (LC-100) offers an excellent method for studying the orientation behavior of micro-arthropods.  相似文献   
989.
990.
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