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   2794篇
  免费   123篇
  2917篇
  2021年   31篇
  2020年   58篇
  2019年   46篇
  2018年   67篇
  2017年   73篇
  2016年   85篇
  2015年   54篇
  2014年   54篇
  2013年   286篇
  2012年   124篇
  2011年   115篇
  2010年   61篇
  2009年   62篇
  2008年   102篇
  2007年   99篇
  2006年   94篇
  2005年   77篇
  2004年   64篇
  2003年   74篇
  2002年   71篇
  2001年   52篇
  2000年   74篇
  1999年   40篇
  1998年   50篇
  1997年   35篇
  1996年   27篇
  1994年   27篇
  1993年   27篇
  1992年   36篇
  1991年   51篇
  1990年   30篇
  1989年   35篇
  1988年   24篇
  1987年   29篇
  1986年   24篇
  1985年   32篇
  1984年   21篇
  1983年   21篇
  1982年   30篇
  1981年   33篇
  1980年   32篇
  1979年   31篇
  1978年   28篇
  1977年   20篇
  1975年   33篇
  1974年   36篇
  1973年   29篇
  1972年   25篇
  1971年   22篇
  1968年   20篇
排序方式: 共有2917条查询结果,搜索用时 15 毫秒
901.
Coenzyme Q10 (CoQ10) is a powerful antioxidant that buffers the potential adverse consequences of free radicals produced during oxidative phosphorylation in the inner mitochondrial membrane. Oxidative stress, resulting in glutathione loss and oxidative DNA and protein damage, has been implicated in many neurodegenerative disorders, including Alzheimer's disease, Parkinson's disease, and Huntington's disease. Experimental studies in animal models suggest that CoQ10 may protect against neuronal damage that is produced by ischemia, atherosclerosis and toxic injury. Though most have tended to be pilot studies, there are published preliminary clinical trials showing that CoQ10 may offer promise in many brain disorders. For example, a 16-month randomized, placebo-controlled pilot trial in 80 subjects with mild Parkinson's disease found significant benefits for oral CoQ10 1,200 mg/day to slow functional deterioration. However, to date, there are no published clinical trials of CoQ10 in Alzheimer's disease. Available data suggests that oral CoQ10 seems to be relatively safe and tolerated across the range of 300-2,400 mg/day. Randomized controlled trials are warranted to confirm CoQ10's safety and promise as a clinically effective neuroprotectant.  相似文献   
902.
When viewing an event in which an object moves behind an occluder on part of its trajectory, 4-month-old infants perceive the trajectory as continuous only when time or distance out of sight is short. Little is known, however, about the conditions under which young infants perceive trajectories to be discontinuous. In the present studies we focus first on infants' perception of trajectories that change during a period of occlusion. Four-month-olds perceive discontinuity in trajectories that change in height or orientation while behind an occluder, and this is true even when a change in direction could be due to an invisible bouncing collision with a surface. Further experiments reveal that infants do not perceive diagonal linear trajectories as continuous across an occlusion unless the occluding and revealing edges are orthogonal to the path of movement. Implications for theories of perceptual and cognitive development are discussed.  相似文献   
903.
904.
The authors manipulated emotion regulation strategies at encoding and administered explicit and implicit memory tests. In Experiment 1, participants used reappraisal to enhance and decrease the personal relevance of unpleasant and neutral pictures. In Experiment 2, decrease cues were replaced with suppress cues that directed participants to inhibit emotion-expressive behavior. Across experiments, using reappraisal to enhance the personal relevance of pictures improved free recall. By contrast, attempting to suppress emotional displays tended to impair recall, especially compared to the enhance condition. Using reappraisal to decrease the personal relevance of pictures had different effects depending on picture type. Paired with unpleasant pictures, the decrease cue tended to improve recall. Paired with neutral stimuli, the decrease cue tended to impair recall. Emotion regulation did not affect perceptual priming. Results highlight dissociable effects of emotion regulation on explicit and implicit memory, as well as dissociations between regulation strategies with respect to explicit memory.  相似文献   
905.
Social Neuroscience: Progress and Implications for Mental Health   总被引:3,自引:0,他引:3  
ABSTRACT— Social neuroscience is a new, interdisciplinary field devoted to understanding how biological systems implement social processes and behavior. Social neuroscience capitalizes on biological concepts and methods to inform and refine theories of social behavior, and it uses social and behavioral constructs and data to inform and refine theories of neural organization and function. We focus here on the progress and potential of social neuroscience in the area of mental health. Research in social neuroscience has grown dramatically in recent years. Among the most active areas of research we found are brain-imaging studies in normal children and adults; animal models of social behavior; studies of stroke patients; imaging studies of psychiatric patients; and research on social determinants of peripheral neural, neuroendocrine, and immunological processes. We also found that these areas of research are proceeding along largely independent trajectories. Our goals in this article are to review the development of this field, examine some currently promising approaches, identify obstacles and opportunities for future advances and integration, and consider how this research can inform work on the diagnosis and treatment of mental disorders.  相似文献   
906.
From birth, infants prefer to look at faces that engage them in direct eye contact. In adults, direct gaze is known to modulate the processing of faces, including the recognition of individuals. In the present study, we investigate whether direction of gaze has any effect on face recognition in four-month-old infants. Four-month infants were shown faces with both direct and averted gaze, and subsequently given a preference test involving the same face and a novel one. A novelty preference during test was only found following initial exposure to a face with direct gaze. Further, face recognition was also generally enhanced for faces with both direct and with averted gaze when the infants started the task with the direct gaze condition. Together, these results indicate that the direction of the gaze modulates face recognition in early infancy.  相似文献   
907.
This article describes emotionally focused couple therapy and the contribution of this model to the field of couple therapy. A focus on emotional processing in the present moment, on process factors and on a genuine empathic connection with both clients is at the heart of this model. The creation of new patterns of emotional responses results in the creation of key new interactional responses. EFT is empirically validated on several levels: on the level of treatment outcome, and on the levels of the relational theory in which it is based and key moments and factors in the change process.  相似文献   
908.
Personality traits show normative patterns of development toward maturity during adolescence. Yet individuals follow these normative patterns to differing degrees. This study used growth mixture modeling to characterize personality development patterns and their associations with outcomes in a population-based sample of 1,537 girls aged 14 to 24. The authors used latent class analysis to identify 3 trajectory groups labeled alright (47%), growing up (42%), and trouble (11%). Alright group members were more likely at age 24 to have completed college, remained involved with their families, and obtained good jobs. Trouble group members were more likely to be involved with drugs and alcohol, to display interpersonal problems, and to behave antisocially. Growing up group members fell in between.  相似文献   
909.
Small deviations from bilateral symmetry (fluctuating asymmetries) are cues to fitness differences in some animals. Therefore, researchers have considered whether animals use these small asymmetries as visual cues to determine appropriate behavioral responses (e.g., mate preferences). However, there have been few systematic studies of animals' abilities to visually discriminate such minor asymmetries. If the asymmetries cannot be discriminated, fluctuating asymmetry can not be a visual cue. Here, we report an investigation of European starlings' (Sturnus vulgaris) abilities to discriminate small size asymmetries. We trained starlings, through operant conditioning in a free-flight aviary, to discriminate achromatic, symmetric paired stimuli from size-matched asymmetric stimuli. By starting the learning process with a large asymmetry and progressing through sequential trials of decreasing asymmetry, we elucidated a behavioral limit to asymmetry discrimination. We found that starlings are capable of discriminating a 10% size asymmetry. There was weaker evidence for discrimination of 5% asymmetry but no evidence for signal discrimination at 2.5% size asymmetry. This level of asymmetry discrimination suggests that many size asymmetry cues in nature can be discriminated by birds. At each level of asymmetry discrimination, we also tested whether starlings could generalize their learned symmetry preference to unreinforced novel images. Consistent with previous findings, we found that starlings could generalize their symmetry preferences.  相似文献   
910.
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