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   395篇
  免费   22篇
  417篇
  2024年   3篇
  2023年   8篇
  2022年   8篇
  2021年   8篇
  2020年   15篇
  2019年   13篇
  2018年   18篇
  2017年   21篇
  2016年   20篇
  2015年   9篇
  2014年   14篇
  2013年   54篇
  2012年   22篇
  2011年   25篇
  2010年   15篇
  2009年   9篇
  2008年   18篇
  2007年   16篇
  2006年   18篇
  2005年   7篇
  2004年   8篇
  2003年   14篇
  2002年   5篇
  2000年   5篇
  1999年   3篇
  1998年   3篇
  1997年   2篇
  1996年   3篇
  1995年   5篇
  1994年   2篇
  1993年   2篇
  1992年   5篇
  1991年   2篇
  1990年   5篇
  1988年   3篇
  1986年   1篇
  1985年   1篇
  1984年   3篇
  1983年   1篇
  1982年   5篇
  1981年   2篇
  1979年   3篇
  1978年   2篇
  1977年   1篇
  1975年   1篇
  1974年   2篇
  1971年   1篇
  1969年   1篇
  1966年   2篇
  1965年   1篇
排序方式: 共有417条查询结果,搜索用时 15 毫秒
91.
Two studies investigated the impact of past ingroup experiences on individual aspirations and effort. Participants were told that in the past, members of their group had either been offered no opportunities (closed), few opportunities (token), or equal opportunities (open) to achieve a desired outcome. The results show that past group experiences determine responses to current opportunities and affect the perceived feasibility of individual success as well as individual performance. Exposure to a token system has different effects, depending on whether the group is historically advantaged or disadvantaged. Whereas those with a collective history of success see token mobility as a challenge and show superior performance, the same situation constitutes a threat to members of a historically disadvantaged group, who fail to take advantage of the opportunities offered to them and perform suboptimally.  相似文献   
92.
To study the effects of different types or durations of stressors on immune functions, male Fischer rats were exposed to chronic physical (electric foot shock) or psychological (non-foot shock) stress induced in the communication box. Superoxide production by alveolar macrophages (AMs), mitogen-induced splenic lymphocyte proliferation, and splenic natural killer (NK) cell cytolysis were examined in vitro. Repeated exposure to physical stress suppressed superoxide production by AMs (-58%, p<0.05 for opsonized zymosan (OZ) and -51%, p<0.05 for phorbol 12-myristate 13-acetate (PMA)), although psychological stress suppressed superoxide production after 24 h of repeated exposures (-40%, p<0.05 for OZ and -47%, p<0.05 for PMA). Acute suppression of the blastic response of splenic lymphocytes was only found in the physical stress group (p<0.05), although the chronic effects were only found in the psychological stress group (p<0.05). NK cell activity was suppressed immediately after the acute physical stress (-30%, p<0.05), but no effects were found in the psychological stress group. These results underline the importance of distinguishing between physical versus psychological stressors when examining the effects of stress on immune functions.  相似文献   
93.
In a series of four experiments, observers identified a briefly flashed line segment more accurately when it was part of a drawing that looked unitary and three-dimensional than when the line segment was presented alone. This extends earlier findings of better identification of a line segment when it is part of an apparently unitary, three-dimensional drawing than when it is in a less coherent flat design; and these results demonstrate a visua1 effect analogous to the word-letter effect which uses nonlinguistic materials. Experiment 1 demonstrates the existence of the object-line effect and shows that it does not depend on the presence of a subsequent mask; Experiment 2 shows that the effect holds up with two-altemative forcedchoice presentation; Experiment 3 demonstrates that the effect is not due to bright end points which may occur when the target line appears with a context; and Experiment 4 shows that the effect is as strong when the target line segments occupy widely separated spatial locations as it is when they occupy nearby, potentially confusable locations.  相似文献   
94.
95.
Despite the extensive evaluation of school-based interventions for bullying, victimization remains a significant problem in schools. Bullying victimization is significantly predicted by contextual (school-related) factors. As a consequence whole-school programs have been commonly used to prevent and reduce bullying victimization. Evidence also points to individual risk factors (such as emotional distress) in predicting victimization, yet programs to prevent bullying victimization by changing these individual risks are far less developed. Few studies have approximated “real-world” implementation conditions in their trials. The current effectiveness trial evaluated the combination of a whole-school program designed to prevent bullying perpetration and victimization together with a targeted intervention for at-risk students, teaching them individual and dyadic strategies to reduce their anxiety and manage victimization, allowing schools some latitude to implement programs as they typically would. Students from Grades 3 and 4 (N = 8,732) across 135 schools were randomly assigned to one of four conditions: combined intervention; whole-school intervention only; individual intervention only; and care as usual. Victimization decreased significantly and similarly across all four conditions at 12 and 24 months following baseline. Similar reductions and failure to discriminate conditions were found on other key constructs: anxiety; bullying perpetration; and depression. Possible reasons for the failure to demonstrate victimization prevention differences and lessons learned from this large, effectiveness trial are considered.  相似文献   
96.
The present purpose is to provide clinicians, occupational and physical therapists, and educators with a comparative analysis of three tests of motor proficiency. The Bruininks-Oseretsky Test of Motor Proficiency, Movement Assessment Battery for Children, and Tufts Assessment of Motor Performance were developed to assess the motor skills of children with developmental delays. The selection criteria, interrater reliability, reproducibility, and recommended use of each test are reported here. Recommendations for use of each test include standardization of the sample population to ensure its appropriateness.  相似文献   
97.
Low target prevalence is a stubborn source of errors in visual search tasks   总被引:1,自引:0,他引:1  
In visual search tasks, observers look for targets in displays containing distractors. Likelihood that targets will be missed varies with target prevalence, the frequency with which targets are presented across trials. Miss error rates are much higher at low target prevalence (1%-2%) than at high prevalence (50%). Unfortunately, low prevalence is characteristic of important search tasks such as airport security and medical screening where miss errors are dangerous. A series of experiments show this prevalence effect is very robust. In signal detection terms, the prevalence effect can be explained as a criterion shift and not a change in sensitivity. Several efforts to induce observers to adopt a better criterion fail. However, a regime of brief retraining periods with high prevalence and full feedback allows observers to hold a good criterion during periods of low prevalence with no feedback.  相似文献   
98.
Although neuroimaging techniques have proven powerful in assessing neural responses, little is known about whether scanner-based neural activity relates to real-world psychological experience. A joint functional magnetic resonance imaging (fMRI)/experience-sampling study investigated whether individual differences in neurocognitive reactivity to scanner-based social rejection related to: (a) moment-to-moment feelings of social rejection during real-world social interactions ("momentary social distress") and (b) the extent to which these momentary feelings corresponded with end-of-day global assessments of social disconnection ("end-of-day social disconnection"). Individuals who showed greater activity in regions associated with affective and pain processing (dorsal anterior cingulate cortex, amygdala, periaqueductal gray) during scanner-based social rejection reported feeling greater momentary social distress during their daily social interactions. In contrast, individuals who showed greater activity in regions associated with memory and self-referential memory encoding (hippocampus, medial prefrontal cortex) showed a stronger correspondence between momentary social distress and end-of-day social disconnection, such that greater momentary social distress was associated with greater end-of-day social disconnection. These findings complement previous work showing a dissociation between momentary and retrospective reports of affect and suggest that these processes rely on dissociable neural systems.  相似文献   
99.
Over the past decade, a number of well-controlled studies have supported the validity of a cognitive model of generalized anxiety disorder (GAD) that has four main components: intolerance of uncertainty, positive beliefs about worry, negative problem orientation, and cognitive avoidance. Although these studies have shown that the model components are associated with high levels of worry in nonclinical samples and with a diagnosis of GAD in clinical samples, they have not addressed the question of whether the model components can predict the severity of GAD. Accordingly, the present study sought to determine if the model components are related to diagnostic severity, worry severity, and somatic symptom severity in a sample of 84 patients with a primary diagnosis of GAD. All model components were related to GAD severity, although positive beliefs about worry and cognitive avoidance were only modestly associated with the severity of the disorder. Intolerance of uncertainty and negative problem orientation had more robust relationships with the severity of GAD (and with worry severity, in particular). When participants were divided into Mild, Moderate, and Severe GAD groups, intolerance of uncertainty and negative problem orientation distinguished the Moderate and Severe GAD groups from the Mild GAD group, even when age, gender, and depressive symptoms were statistically controlled. Overall, the results lend further support to the validity of the model and suggest that intolerance of uncertainty and negative problem orientation are related to the severity of GAD, independently of sociodemographic and associated clinical factors. The theoretical and clinical implications of the findings are discussed.  相似文献   
100.
The ability of cows (Bos taurus) to perceive depth has never been experimentally investigated. If cows can perceive depth, the milking pit in commercial milking facilities may be fear provoking for dairy cows, as past research has shown that most land-dwelling species possess an instinctive fear of heights. In the current study, 12 dairy heifers (1-year-old cows) were exposed to a milking pit (depth-exposed group) and 13 heifers (control group) were exposed to a standard change in the environment while they moved through a milking facility over a 5-day treatment period. Heifers in the depth-exposed group showed a higher heart rate (p < .05) and stopped more often (p < .05) than did those in the control group; persistence of heart rate but not of behavioral responses on repeated exposures indicated that some habituation to the depth stimulus had occurred. Depth exposure had no effect on cortisol concentrations or on ease of handling. These results indicate that heifers responded differently to a change in depth than they did to a standard change in the environment and provide evidence of both depth perception and acute fear of heights in cows.  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