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   857篇
  免费   19篇
  国内免费   7篇
  2021年   7篇
  2020年   10篇
  2019年   11篇
  2018年   16篇
  2017年   8篇
  2016年   17篇
  2014年   8篇
  2013年   46篇
  2012年   21篇
  2011年   13篇
  2010年   13篇
  2009年   11篇
  2008年   14篇
  2007年   24篇
  2006年   14篇
  2005年   12篇
  2004年   21篇
  2003年   13篇
  2002年   21篇
  2001年   35篇
  2000年   46篇
  1999年   20篇
  1998年   11篇
  1997年   8篇
  1992年   18篇
  1991年   15篇
  1990年   34篇
  1989年   23篇
  1988年   11篇
  1987年   23篇
  1986年   31篇
  1985年   21篇
  1984年   21篇
  1983年   16篇
  1982年   8篇
  1981年   10篇
  1980年   8篇
  1979年   12篇
  1978年   10篇
  1976年   7篇
  1975年   15篇
  1974年   15篇
  1973年   20篇
  1972年   14篇
  1971年   17篇
  1970年   15篇
  1969年   7篇
  1968年   9篇
  1967年   10篇
  1951年   6篇
排序方式: 共有883条查询结果,搜索用时 265 毫秒
721.
People rely on support from others to accomplish mundane and momentous tasks. When asking for assistance, is it beneficial to incentivize a helper by offering a motivated gift (i.e., a gift with the hope of getting support in return)? Six studies (N > 2,500) examine the frequency and potential costs of motivated gifts. In Study 1, a third of Americans indicated that they had given a motivated gift at least once, while nearly two‐thirds believed they had received one. In Studies 2a–d, most participants who imagined receiving a motivated gift before a favor request reported lower willingness to help and anticipated satisfaction from helping than participants who imagined simply being asked for a favor. Finally, Study 3 replicates these findings with actual help provided among friends in a laboratory setting. Findings suggest that motivated gifts are relatively common but may sometimes undermine the assistance that people hope to receive.  相似文献   
722.
The authors review previous examinations of the American Counseling Association's (ACA) Journal of Counseling & Development (JCD), consider various editors' policies that shaped the Journal, and update L. W. Harmon and H. E. Harker's (1989) analysis of special interest topics featured in JCD. Studying the flagship professional journal of ACA provides insight into the evolution and development of the profession of counseling.  相似文献   
723.
Recently it was shown that holeboard training can reinforce, i.e., transform early-LTP into late-LTP in the dentate gyrus during the initial formation of a long-term spatial reference memory in rats. The consolidation of LTP as well as of the reference memory was dependent on protein synthesis. We have now investigated the transmitter systems involved in this reinforcement and found that LTP-consolidation and memory retrieval were dependent on β-adrenergic, dopaminergic, and mineralocorticoid receptor (MR) activation, whereas glucocorticoid receptors (GRs) were not involved. Blockade of the β-adrenergic signaling pathway significantly increased the number of reference memory errors compared with MR and dopamine receptor inhibition. In addition, β-adrenergic blockade impaired the working memory. Therefore, we suggest that β-adrenergic receptor activation is the main signaling system required for the retrieval of spatial memory. In addition, other modulatory interactions such as dopaminergic as well as MR systems are involved. This result points to specific roles of different modulatory systems during the retrieval of specific components of spatial memory. The data provide evidence for similar integrative interactions between different signaling systems during cellular memory processes.  相似文献   
724.
TheSimon effect refers to the observation that subjects identify targets (e.g., colors) faster when the irrelevant spatial location of the target corresponds to the location of the response key. Theoretical accounts of the Simon effect typically explain performance in terms of automatic and controlled processes. Furthermore, the relative contributions of automatic and controlled processes are held to change as a function of the proportion of compatible to incompatible trials (compatibility proportion). Data are presented demonstrating that the reliability of the Simon effect, indexed by correlating its magnitude within subjects across blocks of trials, varied substantially as a function of the compatibility proportion. When the compatibility proportion was high, so was reliability. When the compatibility proportion was low, reliability was low as well. The results are discussed in terms of the relative reliability of automatic and controlled processes and the role of working memory and attentional control in goal maintenance.  相似文献   
725.
726.
After prolonged viewing of a slowly drifting or rotating pattern under strict fixation, the pattern appears to slow down and then momentarily stop. The authors show that grouping can slow down the process of "motion fading," suggesting that cortical configural form analysis interacts with the computation of motion signals during motion fading. The authors determined that grouping slows motion fading because it can give rise to trackable features, such as virtual contour terminators not present in the image, that possess stronger motion signals than would occur in the absence of such trackable features. That a continuously rotating stimulus will eventually be perceived to stop, despite the presence of such trackable features, suggests that the motion-from-form system itself can be fatigued. The finding that stationary form can remain visible even after the motion signal has faded suggests that the neural bases of motion visibility and form visibility arise from different neuronal populations.  相似文献   
727.
This study was aimed at revealing which cognitive processes are lateralized in visual categorizations of "humans" by pigeons. To this end, pigeons were trained to categorize pictures of humans and then tested binocularly or monocularly (left or right eye) on the learned categorization and for transfer to novel exemplars (Experiment 1). Subsequent tests examined whether they relied on memorized features or on a conceptual strategy, using stimuli composed of new combinations of familiar and novel humans and backgrounds (Experiment 2), whether the hemispheres processed global or local information, using pictures with different levels of scrambling (Experiment 3), and whether they attended to configuration, using distorted human figures (Experiment 4). The results suggest that the left hemisphere employs a category strategy and concentrates on local features, while the right hemisphere uses an exemplar strategy and relies on configuration. These cognitive dichotomies of the cerebral hemispheres are largely shared by humans, suggesting that lateralized cognitive systems already defined the neural architecture of the common ancestor of birds and mammals.  相似文献   
728.
The Alternating Brightness Star (ABS) is an illusion that provides insight into the relationship between brightness perception and corner angle. Recent psychophysical studies of this illusion have shown that corner salience varies parametrically with corner angle, with sharp angles leading to strong illusory percepts and shallow angles leading to weak percepts. It is hypothesized that the illusory effects arise because of an interaction between surface corners and the shape of visual receptive fields: sharp surface corners may create hotspots of high local contrast due to processing by center-surround and other early receptive fields. If this hypothesis is correct, early visual neurons should respond powerfully to sharp corners and curved portions of surface edges. Indeed, the primary role of early visual neurons may be to localize the discontinuities along the edges of surfaces. If so, all early visual areas should show greater BOLD responses to sharp corners than to shallow corners. On the other hand, if corner processing is exclusively constrained to certain areas of the brain, only those specific areas will show greater responses to sharp vs shallow corners. To address this we explored the BOLD correlates of the ABS illusion in the human visual cortex using fMRI. We found that BOLD signal varies parametrically with corner angle throughout the visual cortex, offering the first neurophysiological correlates of the ABS illusion. This finding provides a neurophysiological basis for the previously reported psychophysical data that showed that corner salience varied parametrically with corner angle. We propose that all early visual areas localize discontinuities along the edges of surfaces, and that specific cortical corner-processing circuits further establish the specific nature of those discontinuities, such as their orientation.  相似文献   
729.
How do people react to those who have helped them? The authors propose that a recipient's evaluation of a helper's intentions and the recipient's own attitudes about future interactions with the helper depend partly on the recipient's perceptions of how the helper decided to assist: on the basis of affect, of role, or of cost-benefit calculation. When a recipient perceives that the decision was based on affect (i.e., positive feelings about him or her), he or she will be more inclined toward future interaction and reciprocation than if he or she perceives the decision as based on role or cost-benefit calculation. It is proposed that these "decision modes" signal the helper's underlying attitudes about the recipient, which in turn, clarify their relationship. A boundary is also identified: The negative impact of apparent cost-benefit thinking is greatest when the amount of help provided is small. Predictions are confirmed in four studies of actual and experimentally manipulated helping episodes.  相似文献   
730.
Force matching errors following eccentric exercise   总被引:3,自引:0,他引:3  
During eccentric exercise contracting muscles are forcibly lengthened, to act as a brake to control motion of the body. A consequence of eccentric exercise is damage to muscle fibres. It has been reported that following the damage there is disturbance to proprioception, in particular, the senses of force and limb position. Force sense was tested in an isometric force-matching task using the elbow flexor muscles of both arms before and after the muscles in one arm had performed 50 eccentric contractions at a strength of 30% of a maximum voluntary contraction (MVC). The exercise led to an immediate reduction of about 40%, in the force generated during an MVC followed by a slow recovery over the next four days, and to the development of delayed onset muscle soreness (DOMS) lasting about the same time. After the exercise, even though participants believed they were making an accurate match, they made large matching errors, in a direction where the exercised arm developed less force than the unexercised arm. This was true whichever arm was used to generate the reference forces, which were in a range of 5-30% of the reference arm's MVC, with visual feedback of the reference arm's force levels provided to the participant. The errors were correlated with the fall in MVC following the exercise, suggesting that participants were not matching force, but the subjective effort needed to generate the force: the same effort producing less force in a muscle weakened by eccentric exercise. The errors were, however, larger than predicted from the measured reduction in MVC, suggesting that factors other than effort might also be contributing. One factor may be DOMS. To test this idea, force matches were done in the presence of pain, induced in unexercised muscles by injection of hypertonic (5%) saline or by the application of noxious heat to the skin over the muscle. Both procedures led to errors in the same direction as those seen after eccentric exercise.  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