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   4879篇
  免费   304篇
  国内免费   2篇
  2023年   54篇
  2022年   52篇
  2021年   83篇
  2020年   141篇
  2019年   173篇
  2018年   214篇
  2017年   217篇
  2016年   274篇
  2015年   153篇
  2014年   158篇
  2013年   554篇
  2012年   286篇
  2011年   300篇
  2010年   171篇
  2009年   170篇
  2008年   215篇
  2007年   222篇
  2006年   193篇
  2005年   158篇
  2004年   161篇
  2003年   153篇
  2002年   132篇
  2001年   73篇
  2000年   58篇
  1999年   51篇
  1998年   54篇
  1997年   47篇
  1996年   43篇
  1995年   49篇
  1994年   39篇
  1993年   25篇
  1992年   32篇
  1991年   27篇
  1989年   20篇
  1988年   24篇
  1987年   24篇
  1986年   17篇
  1985年   29篇
  1984年   27篇
  1983年   27篇
  1982年   31篇
  1981年   30篇
  1980年   18篇
  1979年   22篇
  1978年   19篇
  1977年   20篇
  1976年   19篇
  1975年   18篇
  1974年   17篇
  1971年   17篇
排序方式: 共有5185条查询结果,搜索用时 218 毫秒
891.
Participants (31 young, 27 young–old, and 28 old–old) read 12 narratives, pausing periodically to think aloud. The resulting protocols were analysed for 17 types of inferences and for non‐content (off‐target) information. Factor analysis yielded three inference factors: character, causal and physical. Age difference across these factors were not significant, suggesting that inferential processing architecture may be stable. Each narrative also included an unfamiliar word. Immediately following each narrative, four definition choices and a definition rating scale were presented. The definition scores of old–old adults were lower than young and young–old. In addition, definition scores were negatively related to non‐content comment counts. Taken together, these findings suggest that off‐target working‐memory intrusions may interfere with interpretation specificity in older adults even though semantic architecture remains stable. This study extends the aging and inference literature by addressing age‐related changes across categories of inferential processing and by including a sample of old–old adults. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   
892.
Finding direct and indirect influences of salient psychosocial and situational variables on problem substance use among homeless people is important in designing evidence-based, effective, and relevant interventions for this special population. A stress-coping paradigm in conjunction with situational items specialized for homeless people was used to explore predictive relationships in a sample of homeless adults (N = 664) among (a) psychosocial variables of self-esteem, social support, positive and negative coping, and emotional distress, (b) situational variables of homelessness history and quality of recent housing, and (c) outcomes of alcohol use, injection drug use (IDU), and non-IDU. Lower self-esteem predicted greater emotional distress, lower positive coping, greater negative coping, and more alcohol use. Social support predicted less emotional distress and more positive coping. Chronic homelessness predicted more emotional distress, less positive coping, greater alcohol use, and IDU. Poor housing was associated with more alcohol use and IDU. Substance abuse interventions among the homeless should have a dual focus that includes attention to psychological issues and negative coping patterns while also addressing situational, environmental factors, including encouraging provision of permanent supportive housing.  相似文献   
893.
Chris Fraser 《亚洲哲学》2008,18(2):123-147
Three views of psychological emptiness, or xū, can be found in the Zhuāngz?. The instrumental view values xū primarily as a means of efficacious action. The moderate view assigns it intrinsic value as an element of one Zhuangist vision of the good life. The radical view also takes it to be an element of the ideal life, but in this case the form of life advocated is that of the Daoist sage, who transcends mundane human concerns to merge with nature or the Dào. The instrumental and moderate views articulate a relatively commonsensical position, on which the agent continues to pursue at least some characteristically human projects. On the radical view, by contrast, the agent ceases to exercise agency and lives a life hardly recognizable as human. The three views thus signal a tension in Zhuangist ethics, and the unattractiveness of the radical view poses a potential obstacle to the application of Daoist ideas in contemporary ethical discourse. The paper argues that there are principled grounds within Zhuangist thought for detaching the instrumental and moderate views from the radical view and rejecting the latter.  相似文献   
894.
Hair analysis has been used to reflect long-term systemic exposure to exogenous drugs and toxins. Several studies have demonstrated the feasibility of measuring endogenous steroid hormones, e.g. cortisol, in hair. Recently, a study in macaques showed a significant increase in hair cortisol levels induced by stress. We explored whether hair cortisol levels may be used as a biomarker for long-term stress in humans. Patients with severe chronic pain, aged 18 years or older, receiving opioid treatment for at least one year were recruited. Controls were non-obese (body mass index, BMI < 30 mg/kg(2)) adults. The Perceived Stress Scale (PSS) questionnaire was used to assess perceived stress over the last 4 weeks. A hair sample was obtained from the vertex posterior. Cortisol was measured using an enzyme-linked immunosorbent assay. We included fifteen patients (nine females and six males) and 39 non-obese control subjects (20 females, 19 males). PSS scores (median and range) were significantly higher in chronic pain patients (24: 12-28) than in controls (12: 3-31)(P < 0.001). Hair cortisol contents (median and range) were significantly greater in chronic pain patients (83.1: 33.0-205 g/mg) than in controls (46.1: 27.2-200 pg/mg) (P < 0.01). We conclude that hair cortisol contents are increased in patients with major chronic stress. Measurement of cortisol levels in hair constitutes a novel biomarker of prolonged stress.  相似文献   
895.
896.
This is the first article of a two-part professional development series addressing genetic counseling for personal and family histories of psychiatric disorders. It is based on an Educational Breakout Session presented by the Psychiatric Special Interest Group of the National Society of Genetic Counselors at the 2006 Annual Education Conference. This article examines issues that arise in addressing family histories of psychiatric illness, while the second article in the series considers the generation and provision of individualized recurrence risks for psychiatric disorders. In this article we discuss the importance of managing uncertainty for affected individuals and their close family members who have been referred to genetics for a number of different indications. We then use four simulated cases to make recommendations about the scope and timing of discussions related to the psychiatric family history.  相似文献   
897.
Down syndrome (DS) is a genetic disorder arising from the presence of a third copy of the human chromosome 21 (Hsa21). Recently, O’Doherty and colleagues in an earlier study generated a new genetic mouse model of DS (Tc1) that carries an almost complete Hsa21. Since DS is the most common genetic cause of mental retardation, we have undertaken a detailed analysis of cognitive function and synaptic plasticity in Tc1 mice. Here we show that Tc1 mice have impaired spatial working memory (WM) but spared long-term spatial reference memory (RM) in the Morris watermaze. Similarly, Tc1 mice are selectively impaired in short-term memory (STM) but have intact long-term memory (LTM) in the novel object recognition task. The pattern of impaired STM and normal LTM is paralleled by a corresponding phenotype in long-term potentiation (LTP). Freely-moving Tc1 mice exhibit reduced LTP 1 h after induction but normal maintenance over days in the dentate gyrus of the hippocampal formation. Biochemical analysis revealed a reduction in membrane surface expression of the AMPAR (α-amino-3-hydroxy-5-methyl-4-propionic acid receptor) subunit GluR1 in the hippocampus of Tc1 mice, suggesting a potential mechanism for the impairment in early LTP. Our observations also provide further evidence that STM and LTM for hippocampus-dependent tasks are subserved by parallel processing streams.  相似文献   
898.
899.
Hispanic individuals in the U.S. have been disproportionately impacted by HIV/AIDS, yet little is known regarding the neuropsychological sequelae of HIV within the Hispanic population. This study characterized neuropsychological (NP) test performance of HIV+ English-speaking Hispanic participants (n = 51) and investigated the combined roles of sociocultural factors (e.g., ethnicity, socioeconomic status [SES] proxy, and reading level) on NP test performance among our HIV+ Hispanic and non-Hispanic White participants (n = 49). Results revealed that the pattern of NP impairment in HIV+ Hispanic participants is consistent with the frontal-striatal pattern observed in HIV-associated CNS sequelae, and the overall prevalence of global NP impairment was high compared to previous reports with more ethnically homogeneous, non-Hispanic White cohorts. Multivariate prediction models that considered both sociocultural factors and CD4 count revealed that reading level was the only unique predictor of global NP functioning, learning, and attention/working memory. In contrast, ethnicity was the only unique predictor of abstraction/executive functioning. This study provides support for the use of neuropsychological evaluation in detecting HIV-associated NP impairment among HIV+ Hispanic participants and adds to the growing literature regarding the importance of considering sociocultural factors in the interpretation of NP test performance.  相似文献   
900.
Research on navigation has shown that humans and laboratory animals recover their sense of orientation primarily by detecting geometric properties of large-scale surface layouts (e.g. room shape), but the reasons for the primacy of layout geometry have not been clarified. In four experiments, we tested whether 4-year-old children reorient by the geometry of extended wall-like surfaces because such surfaces are large and perceived as stable, because they serve as barriers to vision or to locomotion, or because they form a single, connected geometric figure. Disoriented children successfully reoriented by the shape of an arena formed by surfaces that were short enough to see and step over. In contrast, children failed to reorient by the shape of an arena defined by large and stable columns or by connected lines on the floor. We conclude that preschool children's reorientation is not guided by the functional relevance of the immediate environmental properties, but rather by a specific sensitivity to the geometric properties of the extended three-dimensional surface layout.  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