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   2449篇
  免费   117篇
  国内免费   2篇
  2568篇
  2020年   43篇
  2019年   40篇
  2018年   57篇
  2017年   61篇
  2016年   55篇
  2015年   47篇
  2014年   55篇
  2013年   253篇
  2012年   88篇
  2011年   95篇
  2010年   69篇
  2009年   79篇
  2008年   108篇
  2007年   87篇
  2006年   73篇
  2005年   59篇
  2004年   76篇
  2003年   68篇
  2002年   61篇
  2001年   48篇
  2000年   64篇
  1999年   53篇
  1998年   38篇
  1997年   36篇
  1996年   31篇
  1995年   22篇
  1994年   27篇
  1993年   24篇
  1992年   32篇
  1991年   36篇
  1990年   26篇
  1989年   25篇
  1988年   25篇
  1987年   31篇
  1986年   20篇
  1985年   30篇
  1984年   24篇
  1983年   22篇
  1982年   20篇
  1981年   22篇
  1979年   31篇
  1978年   23篇
  1977年   25篇
  1976年   32篇
  1975年   26篇
  1974年   28篇
  1973年   21篇
  1971年   22篇
  1966年   23篇
  1965年   19篇
排序方式: 共有2568条查询结果,搜索用时 0 毫秒
201.
202.
African Americans are overrepresented on the organ transplant waiting list and underrepresented among organ and tissue donors. One of the most highly noted reasons for lack of donation is the perception that donation is contrary to religious beliefs. The purpose of this cross-sectional study is to explore the complexities of religion (beliefs, religiosity, and religious involvement) and its association with willingness to donate and the written expression of donation intentions. Findings from a sample of 505 African American participants suggest that religion is a multidimensional construct and results differ depending on how the construct is measured and operationalized.  相似文献   
203.
204.
205.
206.
A paucity of research on thought suppression exists among adolescents. The present study describes the preliminary psychometrics of the Adolescent Thought Control Questionnaire (TCQ-A) and its relationships with internalizing symptomatology in adolescents. Adolescents between 12 and 18 years of age completed the TCQ-A and other self-report instruments. Principal components analysis yielded five-factors theoretically derived from an adult measure: distraction, social, re-appraisal, worry, and punishment control strategies. The five-factor structure was well fitted to the data in a confirmatory factor analysis. Adequate evidence of reliability was obtained; however, internal consistency of the punishment factor was not adequate in the sample. The TCQ-A evidenced convergent and divergent validity with internalizing and externalizing symptomatology respectively. Future research applications of the TCQ-A, suggestions for further analyses, and refinement of the instrument are also discussed.  相似文献   
207.
Number systems—such as the natural numbers, integers, rationals, reals, or complex numbers—play a foundational role in mathematics, but these systems can present difficulties for students. In the studies reported here, we probed the boundaries of people’s concept of a number system by asking them whether “number lines” of varying shapes qualify as possible number systems. In Experiment 1, participants rated each of a set of number lines as a possible number system, where the number lines differed in their structures (a single straight line, a step-shaped line, a double line, or two branching structures) and in their boundedness (unbounded, bounded below, bounded above, bounded above and below, or circular). Participants also rated each of a group of mathematical properties (e.g., associativity) for its importance to number systems. Relational properties, such as associativity, predicted whether participants believed that particular forms were number systems, as did the forms’ ability to support arithmetic operations, such as addition. In Experiment 2, we asked participants to produce properties that were important for number systems. Relational, operation, and use-based properties from this set again predicted ratings of whether the number lines were possible number systems. In Experiment 3, we found similar results when the number lines indicated the positions of the individual numbers. The results suggest that people believe that number systems should be well-behaved with respect to basic arithmetic operations, and that they reject systems for which these operations produce ambiguous answers. People care much less about whether the systems have particular numbers (e.g., 0) or sets of numbers (e.g., the positives).  相似文献   
208.
As a group, cigarette smokers exhibit blunted subjective, behavioral, and neurobiological responses to nondrug incentives and rewards, relative to nonsmokers. Findings from recent studies suggest, however, that there are large individual differences in the devaluation of nondrug rewards among smokers. Moreover, this variability appears to have significant clinical implications, since reduced sensitivity to nondrug rewards is associated with poorer smoking cessation outcomes. Currently, little is known about the neurobiological mechanisms that underlie these individual differences in the responsiveness to nondrug rewards. Here, we tested the hypothesis that individual variability in reward devaluation among smokers is linked to the functioning of the striatum. Specifically, functional magnetic resonance imaging was used to examine variability in the neural response to monetary outcomes in nicotine-deprived smokers anticipating an opportunity to smoke—circumstances found to heighten the devaluation of nondrug rewards by smokers in prior work. We also investigated whether individual differences in reward-related brain activity in those expecting to have access to cigarettes were associated with the degree to which the same individuals subsequently were willing to resist smoking in order to earn additional money. Our key finding was that deprived smokers who exhibited the weakest response to rewards (i.e., monetary gains) in the ventral striatum were least willing to refrain from smoking for monetary reinforcement. These results provide evidence that outcome-related signals in the ventral striatum serve as a marker for clinically meaningful individual differences in reward-motivated behavior among nicotine-deprived smokers.  相似文献   
209.
210.
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