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   2295篇
  免费   127篇
  2023年   21篇
  2022年   12篇
  2021年   32篇
  2020年   54篇
  2019年   79篇
  2018年   87篇
  2017年   80篇
  2016年   102篇
  2015年   52篇
  2014年   69篇
  2013年   294篇
  2012年   111篇
  2011年   123篇
  2010年   81篇
  2009年   46篇
  2008年   74篇
  2007年   81篇
  2006年   81篇
  2005年   66篇
  2004年   82篇
  2003年   61篇
  2002年   54篇
  2001年   25篇
  2000年   33篇
  1999年   24篇
  1998年   23篇
  1997年   24篇
  1996年   20篇
  1995年   12篇
  1994年   15篇
  1993年   18篇
  1992年   16篇
  1991年   19篇
  1990年   16篇
  1989年   14篇
  1988年   15篇
  1987年   14篇
  1986年   15篇
  1985年   24篇
  1984年   26篇
  1983年   19篇
  1982年   21篇
  1981年   21篇
  1980年   22篇
  1979年   22篇
  1978年   19篇
  1977年   14篇
  1976年   20篇
  1975年   20篇
  1974年   21篇
排序方式: 共有2422条查询结果,搜索用时 15 毫秒
281.
282.
Neuroimaging research indicates that human intellectual ability is related to brain structure including the thickness of the cerebral cortex. Most studies indicate that general intelligence is positively associated with cortical thickness in areas of association cortex distributed throughout both brain hemispheres. In this study, we performed a cortical thickness mapping analysis on data from 182 healthy typically developing males and females ages 9 to 24 years to identify correlates of general intelligence (g) scores. To determine if these correlates also mediate associations of specific cognitive abilities with cortical thickness, we regressed specific cognitive test scores on g scores and analyzed the residuals with respect to cortical thickness. The effect of age on the association between cortical thickness and intelligence was examined. We found a widely distributed pattern of positive associations between cortical thickness and g scores, as derived from the first unrotated principal factor of a factor analysis of Wechsler Abbreviated Scale of Intelligence (WASI) subtest scores. After WASI specific cognitive subtest scores were regressed on g factor scores, the residual score variances did not correlate significantly with cortical thickness in the full sample with age covaried. When participants were grouped at the age median, significant positive associations of cortical thickness were obtained in the older group for g-residualized scores on Block Design (a measure of visual-motor integrative processing) while significant negative associations of cortical thickness were observed in the younger group for g-residualized Vocabulary scores. These results regarding correlates of general intelligence are concordant with the existing literature, while the findings from younger versus older subgroups have implications for future research on brain structural correlates of specific cognitive abilities, as well as the cognitive domain specificity of behavioral performance correlates of normative gray matter thinning during adolescence.  相似文献   
283.
The voting behavior literature has advanced two prominent theoretical models of partisanship: the social psychological and rational models. Implicit to both stylized models is the assumption that all partisans process information similarly. Yet, growing research in psychology suggests that individuals possess different motivations when evaluating information. We propose that the applicability of the stylized models of partisanship is conditioned on individuals' need for cognition (NFC) and need for affect (NFA), with the social psychological model being most applicable to individuals who have a high NFA and the rational model most applicable to those with a high NFC. To test this proposition, we fielded a survey in which respondents who identified with the two major political parties in the United States (Democrat or Republican) were randomly assigned factual information that depicted either their party or their opposing party in a negative light. Respondents were then asked to assess the actions of that party and subsequently evaluate both political parties. We find evidence that is generally consistent with the proposition that the stylized models of partisanship are conditionally dependent on the extent to which individuals possess a need to engage in effortful thinking or a need to seek out emotions.  相似文献   
284.

We estimate a series of multivariate logistic regression models specifying the effects of gender and other variables on the initiation and escalation of alcohol and other substance use/abuse in a sample of young adults from a general population. After controlling for race, ethnicity, father's education, and a tendency to over‐ or underendorse statements, effects of gender on circumstances surrounding initiation/escalation of binge drinking, marijuana use, and use of other illicit drugs were observed to be congruent with the literature on gender‐related sociodevelopmental processes and empirical studies of the circumstances surrounding substance use. Among substance users/abusers, gender was implicated in self‐reports of the relevance of peer influence, needs to enhance self‐importance and a sense of power, conflictive consequences, sensation‐seeking, and reduction of distress in the processes surrounding initiation and escalation of use.  相似文献   
285.
286.
Abstract

Urinary incontinence is a common problem in psychiatric settings, particularly among psychogeriatric patients. In view of the known diuretic action of caffeine, the present study assessed the effect of tea and coffee consumption on level of incontinence in selected psychogeriatric inpatients. A total of 14 patients participated in the study which employed a combined “withdrawal” and “multiple-baseline across subjects” design to examine the effect of alternating phases of caffeine exposure and abstinence on frequency of daytime and nighttime incontinence. Incontinence levels were significantly reduced during periods of caffeine abstinence relative to periods of chronic caffeine exposure. The hypothesis that observed reductions in incontinence may have been due to accompanying reductions in fluid intake was examined but not supported.  相似文献   
287.
The psychosocial determinants of health-impairing physical inactivity among Hispanic populations have not been well explored nor have systematic comparisons been made with White populations using Social Cognitive Theory (SCT) measures. Three exercise-relevant efficacy measures (task, scheduling, and response efficacy), three exercise-relevant expectancy measures (physical health, psychological health, and self-evaluative), and self reports of activity levels were obtained from 20-year-old male and female Hispanics (n?=?94) and Whites (n?=?94). Activity levels for the two groups were analyzed in separate regression analyses that included the six SCT measures and gender as predictors. The set of seven predictors accounted for 51% of the variance in self-reported activity levels in each analysis. For young adult Hispanics, task efficacy, response efficacy, mental-health expectancies, and self-evaluative expectancies predicted activity level. For young adult Whites, scheduling efficacy and self-evaluative expectancies predicted activity level. Gender was not a significant predictor of activity level for either group. A multivariate analysis of variance indicated that the only SCT predictor on which Hispanics and Whites significantly differed was mental-health expectancies. The results of this study indicate that the psychosocial determinants of exercise are qualitatively different for the two groups and that the determinants of physical activity levels for young adult Hispanics may not be as effective as those of young adult Whites in sustaining lifelong exercise habits. Thus the present study offers a promising strategy for detecting inactivity-related physical- and mental-health risks at an age when lifelong habits of physical activity are still being formed.  相似文献   
288.
The present study tested whether baseline perceived social support and social integration predicted baseline and follow-up measures of health-related quality of life for 364 older adults with osteoarthritis. The findings are secondary analyses of a randomized controlled trial of an exercise intervention. Multiple regression analyses indicate that perceived social support was related to baseline measures of functioning in psychological (depressive symptoms, social functioning, and life satisfaction) and physical domains (self-rated disability, observed physical function, and perceived health), after accounting for demographic and clinical status factors. At 18-month follow-up (additionally controlling for exercise intervention and baseline outcomes), social support significantly predicted changes in psychosocial functioning, but was unrelated to changes in self-reported and observed physical health. The findings indicate that social support is an important predictor of long-term psychosocial outcomes, but is less important than baseline clinical status for physical health endpoints in this cohort of older adults. In contrast, social integration was not a consistent predictor of outcomes.  相似文献   
289.
The purpose of this study was to explore whether sedentary behavior cognitions explain physical activity (PA) intention and behavior when integrated within the theory of planned behavior framework (TPB). A random community sample of 206 adults and a sample of 174 undergraduate students completed measures of the TPB pertaining to PA and four popular leisure-time behaviors (TV viewing, computer use, sedentary hobbies, and sedentary socializing) and an adapted Godin Leisure-Time Exercize Questionnaire (community sample = cross-sectional, undergraduate sample = 2-week prospective). Results using ordinary least squares regression provided evidence that TV viewing intention explains additional variance in PA behavior, and affective attitude (community sample) and perceived behavioral control (undergraduate sample) towards TV viewing explains additional variance in PA intention even after controlling for PA-related TPB constructs. These results underscore the potential value of adding sedentary control interventions in concert with PA promotion.  相似文献   
290.
Evidence from a number of investigations suggests a considerable overlap between reading disability (RD) and attention deficit-hyperactivity disorder (ADHD). We investigate the relationship between RD and ADHD in a cohort of 186 children 7.5–9.5 years of age, recruited explicitly to address classification and definitional issues in these disorders. Using multivariate methods, we examine the hypothesis that RD and ADHD represent separate diagnostic entities that frequently co-occur in the same individual. The results suggest that RD is characterized by deficits within the language system, in particular a subcomponent within that system, phonological processing; in contrast, such linguistic deficits are not characteristic of ADHD unless ADHD is associated with RD. When children with both RD and ADHD are examined, both the linguistic deficits associated with RD and the behavioral characteristics associated with ADHD are apparent, but these deficits are not synergistic. We conclude that RD and ADHD represent separate disorders that frequently co-occur.  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