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   2881篇
  免费   86篇
  国内免费   2篇
  2021年   16篇
  2020年   34篇
  2019年   55篇
  2018年   75篇
  2017年   61篇
  2016年   68篇
  2015年   53篇
  2014年   57篇
  2013年   360篇
  2012年   105篇
  2011年   95篇
  2010年   76篇
  2009年   66篇
  2008年   92篇
  2007年   103篇
  2006年   94篇
  2005年   99篇
  2004年   108篇
  2003年   89篇
  2002年   94篇
  2001年   45篇
  2000年   43篇
  1999年   53篇
  1998年   53篇
  1997年   34篇
  1996年   61篇
  1995年   51篇
  1994年   53篇
  1993年   48篇
  1992年   50篇
  1991年   34篇
  1990年   38篇
  1989年   39篇
  1988年   33篇
  1987年   37篇
  1986年   36篇
  1985年   49篇
  1984年   32篇
  1983年   45篇
  1982年   39篇
  1981年   32篇
  1980年   33篇
  1979年   19篇
  1978年   26篇
  1977年   22篇
  1976年   18篇
  1975年   16篇
  1974年   23篇
  1973年   17篇
  1971年   11篇
排序方式: 共有2969条查询结果,搜索用时 15 毫秒
941.
In this study, we examined the association between social discounting and smoking status in a cohort of pregnant cigarette smokers (n = 91), quitters (n = 27), or never‐smokers (n = 30). The smokers and quitters were participants in clinical trials on smoking cessation and relapse prevention, whereas the never‐smokers were controls in a study on nicotine withdrawal during pregnancy. Social discounting was assessed using a paper‐and‐pencil task that assesses the amount of hypothetical money a person is willing to forgo in order to share with individuals in their social network ranging from the person who is emotionally closest to them to a mere acquaintance. The amount that women were willing to forgo in order to share decreased hyperbolically as a function of social distance, with smokers exhibiting steeper discounting functions (i.e., less generosity) than quitters or never‐smokers; discounting functions of quitters and never‐smokers did not differ significantly. In multivariate analyses controlling for potential sociodemographic and other confounds, social discounting remained a significant predictor of smoking status among smokers versus quitters. Overall, these results suggest that individual differences in social discounting may be a factor influencing the choices that women make about quitting smoking upon learning of a pregnancy. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   
942.
Our purpose in undertaking the present study was to examine the hypotheses proposed for explaining the frequent comorbidity of bipolar disorder and multiple sclerosis. One hypothesis posits that, when there is comorbidity, MS plays a causal role in psychiatric manifestations. Another suggests that both disorders have a common underlying physiological process that increases the likelihood of their co-occurrence. We examined two adult siblings with comorbidity and their relatives, including three generations of family members with psychiatric morbidity. We found an extensive multigenerational history of bipolar disorder in this family. This history would seem to support the hypothesis of a common underlying brain process (potentially genetically-based) to explain the comorbidity of BD and MS, but cannot clarify whether this comorbidity implies a relationship between the two disorders or merely reflects parallel processes of brain deterioration. We cannot, however, rule out the possibility of a subclinical MS-related process leading to the early manifestation of BD, with MS appearing much later in time, or even a third, undetermined factor, leading to familial comorbidity. Although we have insufficient information to support either hypothesis definitively, we present the familial cases as a springboard for a discussion of dilemmas related to teasing apart MS and BD comorbidity. Further observation of the clinical course of the younger family members, who have not yet shown any neurological signs, over the next few years may elucidate the current picture further.  相似文献   
943.
Language and concepts are intimately linked, but how do they interact? In the study reported here, we probed the relation between conceptual and linguistic processing at the earliest processing stages. We presented observers with sequences of visual scenes lasting 200 or 250 ms per picture. Results showed that observers understood and remembered the scenes' abstract gist and, therefore, their conceptual meaning. However, observers remembered the scenes at least as well when they simultaneously performed a linguistic secondary task (i.e., reading and retaining sentences); in contrast, a nonlinguistic secondary task (equated for difficulty with the linguistic task) impaired scene recognition. Further, encoding scenes interfered with performance on the nonlinguistic task and vice versa, but scene processing and performing the linguistic task did not affect each other. At the earliest stages of conceptual processing, the extraction of meaning from visually presented linguistic stimuli and the extraction of conceptual information from the world take place in remarkably independent channels.  相似文献   
944.
945.
Although a large body of research has examined the negative outcomes that occur when Latina adolescents engage in sexual activity, relatively little research explores the determinants that may contribute to these behaviors. In the current study, an ecological community psychological approach was used to examine the impact that substance use, sexual self-efficacy, parental communication, normative peer pressure, acculturation, educational aspirations, grades, and gang activity have on adolescent sexual behavior. The sample consisted of 217 participants (mean age of 14.6) who self-identified as Latina from the greater Los Angeles metropolitan area of California in the United States. The results indicate that about a third of the sample had engaged in one or more sexual behaviors. Overall, greater usage of substances was associated with greater numbers of sexual behaviors. Girls who reported engaging in two or more sexual behaviors reported more frequent marijuana and alcohol use. The girls who reported high sexual self-efficacy engaged in few to no sexual behaviors. Additionally, parental communication, normative peer pressure, acculturation, and educational aspirations were unrelated to their sexual behavior. However, the majority of girls who reported receiving good grades also reported no sexual activity. Moreover, girls who reported no sexual behavior also reported no gang activity. The results indicate that a multi-level approach to examining the psycho-social determinants of sexual activity in Latina girls provides a more comprehensive picture of their sexual decision making.  相似文献   
946.
Reports an error in "Age of onset of marijuana use and executive function" by Staci A. Gruber, Kelly A. Sagar, Mary Kathryn Dahlgren, Megan Racine and Scott E. Lukas (Psychology of Addictive Behaviors, Advanced Online Publication, Nov 21, 2011, np). Figure 1 should have been presented in color. All versions of this article have been corrected. (The following abstract of the original article appeared in record 2011-27123-001.) Marijuana (MJ) remains the most widely abused illicit substance in the United States, and in recent years, a decline in perceived risk of MJ use has been accompanied by a simultaneous increase in rates of use among adolescents. In this study, the authors hypothesized that chronic MJ smokers would perform cognitive tasks, specifically those that require executive function, more poorly than control subjects and that individuals who started smoking MJ regularly prior to age 16 (early onset) would have more difficulty than those who started after age 16 (late onset). Thirty-four chronic, heavy MJ smokers separated into early and late onset groups, and 28 non-MJ smoking controls completed a battery of neurocognitive measures. As hypothesized, MJ smokers performed more poorly than controls on several measures of executive function. Age of onset analyses revealed that these between-group differences were largely attributed to the early onset group, who were also shown to smoke twice as often and nearly 3 times as much MJ per week relative to the late onset smokers. Age of onset, frequency, and magnitude of MJ use were all shown to impact cognitive performance. Findings suggest that earlier MJ onset is related to poorer cognitive function and increased frequency and magnitude of MJ use relative to later MJ onset. Exposure to MJ during a period of neurodevelopmental vulnerability, such as adolescence, may result in altered brain development and enduring neuropsychological changes. (PsycINFO Database Record (c) 2012 APA, all rights reserved).  相似文献   
947.
Parental depression places offspring at elevated risk for multiple, co-occurring problems. The purpose of this study was to develop and preliminarily evaluate Project Hope, a family intervention for the prevention of both depression and substance use among adolescent-aged children (M?=?13.9?years) of depressed parents. The program was created by blending two empirically supported interventions: one for depression and another for substance use. Thirty families were randomly assigned to either Project Hope (n?=?16) or a wait-list control condition (n?=?14). Pretests, posttests (n?=?29), and 5-month follow-ups (n?=?28) were conducted separately with parents and youth via phone interviews. Questions asked about the family depression experience, family interactions, family management, coping, adolescent substance use beliefs and refusal skills, adolescent depression, and adolescent substance use. Project Hope was fully developed, manualized, and implemented with a small sample of targeted families. Engagement in the program was relatively high. Preliminary outcome analyses were conducted using 2 (Group) ×3 (Time) analyses of covariance. Results provided some evidence for significant improvements among intervention compared to control participants in indicators of the family depression experience, family management, and coping, and a statistically significant decrease from pretest to posttest in alcohol quantity for intervention compared to control youth. Next steps for this program of research are discussed.  相似文献   
948.
The community mental health (CMH) system provides treatment for behavioral and psychiatric problems in children with autism spectrum disorders (ASD). Although parent stakeholder perspectives are important to improving care, these perspectives have not been systematically examined for this population in the CMH sector. Twenty-one semi-structured qualitative interviews were conducted with parents of children with ASD who received services in CMH clinics. Themes related to child clinical histories, service access and experiences with the CMH system revealed a specific trajectory of service need identification, obtaining a diagnosis, and experience with services. Each trajectory stage was marked by high parent stress. Results provide information about the characteristics of children with ASD served in community mental health clinics and direction for targeted improvement efforts.  相似文献   
949.
The bimanual coupling literature supposes an inherent drive for synchrony between the upper limbs when making discrete bimanual movements. The level of synchrony is argued to be task dependent, reliant on the visual demands of the two targets, and the result of a complex pattern of hand and eye movements (Bingham, Hughes, & Mon-Williams, 2008 ; Riek, Tresilian, Mon-Williams, Coppard, & Carson, 2003 ). However, recent work by Bruyn and Mason ( 2009 ) suggests that temporal coordination is not solely influenced by visual saccades. In this experimental series, a total of 8 participants performed congruent movements to targets either near or far from the midline. Targets far from the midline, requiring a visual saccade, resulted in greater terminal asynchrony. Initial and terminal asynchrony were not consistent, but linked to the task demands at that stage of the movement. If the asynchrony evident at the end of a bimanual movement is due to a complex pattern of hand and eye movements then the removal of visual feedback should result in an increase in synchrony. Sixteen participants then completed congruent and incongruent bimanual aiming movements to near and/or far targets. Movements were made with or without visual feedback of hands and targets. Analyses revealed that movements made without visual feedback showed increased synchrony between the limbs, yet movements to incongruent targets still showed greater asynchrony. We suggest that visual constraints are not the sole cause of asynchrony in discrete bimanual movements.  相似文献   
950.
Face and symmetry processing have common characteristics, and several lines of evidence suggest they interact. To characterize their relationship and possible interactions, in the present study we created a novel library of images in which symmetry and face-likeness were manipulated independently. Participants identified the target that was most symmetric among distractors of equal face-likeness (Experiment 1) and identified the target that was most face-like among distractors of equal symmetry (Experiment 2). In Experiment 1, we found that symmetry judgments improved when the stimuli were more face-like. In Experiment 2, we found a more complex interaction: Image symmetry had no effect on detecting frontally viewed faces, but worsened performance for nonfrontally viewed faces. There was no difference in performance for upright versus inverted images, suggesting that these interactions occurred on the parts-based level. In sum, when symmetry and face-likeness are independently manipulated, we find that each influences the perception of the other, but the nature of the interactions differs.  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