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   32347篇
  免费   1228篇
  国内免费   18篇
  2020年   308篇
  2019年   428篇
  2018年   600篇
  2017年   632篇
  2016年   604篇
  2015年   450篇
  2014年   498篇
  2013年   2508篇
  2012年   887篇
  2011年   1016篇
  2010年   667篇
  2009年   636篇
  2008年   917篇
  2007年   839篇
  2006年   800篇
  2005年   663篇
  2004年   611篇
  2003年   658篇
  2002年   607篇
  2001年   1198篇
  2000年   1183篇
  1999年   849篇
  1998年   374篇
  1997年   305篇
  1996年   304篇
  1994年   314篇
  1992年   722篇
  1991年   699篇
  1990年   666篇
  1989年   614篇
  1988年   585篇
  1987年   579篇
  1986年   548篇
  1985年   612篇
  1984年   476篇
  1983年   372篇
  1979年   462篇
  1978年   346篇
  1977年   327篇
  1976年   307篇
  1975年   415篇
  1974年   417篇
  1973年   475篇
  1972年   384篇
  1971年   319篇
  1970年   307篇
  1969年   327篇
  1968年   378篇
  1967年   333篇
  1966年   385篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
We examined the effects of a self-monitoring program on reducing the frequency of negative statements of a student with mild mental retardation who was enrolled in a self-contained classroom at a middle school. A changing criterion design was used within a multiple baseline design across two classroom periods. Additionally, the frequency of positive statements was reported. The results showed a decrease in the number of negative statements, and an increase in the number of positive statements. Maintenance data collected up to 8 weeks after the program ended indicated that the student continued to emit positive rather than negative statements. The use of this procedure to decelerate undesirable behavior is discussed.  相似文献   
992.
993.
The dead donor rule--that persons must be dead before their organs are taken--is a central part of the moral framework underlying organ procurement. Efforts to increase the pool of transplantable organs have been forced either to redefine death (e.g., anencephaly) or take advantage of ambiguities in the current definition of death (e.g., the Pittsburgh protocol). Society's growing acceptance of circumstances in which health care professionals can hasten a patient's death also may weaken the symbolic importance of the dead donor rule. We consider the implications of these efforts to continually revise the line between life and death and ask whether it would be preferable to abandon the dead donor rule and rely entirely on informed consent as a safeguard against abuse.  相似文献   
994.
The purpose of this paper is twofold. First, it provides an historical overview of studies of risk, risk perception, and decision making under risk within the genetic counseling domain. Second, it proposes an alternative conceptualization and operationalization for the study of risk perception. The conceptualization involves probability, adversity, incompleteness, and ambiguity. Prior studies of risk perception focus on the recurrence risk and operationalize risk perception by asking for interpretations of the magnitude of the probability of the outcome. Their focus is on the probability of a particular outcome. We formulate the problem in terms of a gamble and suggest that risk perception be operationalized in terms of the riskiness of the gamble. Our focus is on the riskiness of a decision option which entails two or more outcomes.  相似文献   
995.
This article describes an important new area of research on services for children and adolescents with mental disorders at the National Institute of Mental Health, the parameters of mental health services research for youth, and the opportunities that are available for grant-funded investigations in this area.  相似文献   
996.
The traditional family composition model of children's divorce adjustment was compared to a family competence model. Subjects included 81 children whose parents remained married, were divorced, or were divorced and subsequently remarried. Divorced families had been separated for between 24 and 48 months. Custodial parents completed questionnaires regarding family functioning, occurrence of stressful life events, and child's psychosocial adjustment. Children completed questionnaires regarding parenting behaviors and self-esteem. A trained examiner conducted a structured diagnostic interview of the child. Multivariate analysis of covariance showed that family composition had a significant effect on the occurrence of stressful events and change in income but not children's adjustment. Hierarchical multiple regression correlations indicated the most powerful predictors of child adjustment were family competence variables which accounted for 21% of the variance in child adjustment scores. In contrast, family composition accounted for only 8% of variance in child adjustment scores. Further, hierarchical multiple regression correlations indicated that higher levels of family functioning were associated with families where parental hostility was low and parents displayed few rejecting behaviors while practicing consistent and appropriate discipline.  相似文献   
997.
Direct-observation procedures were used to objectively and efficiently assess several classes of service provided for individuals residing at two state facilities for the developmentally disabled. Time samples were taken of the condition of the clients' physical environment and of the clients themselves. The ongoing behavior of both clients and staff also was recorded. Each residence was observed at least three times during both regular work hours and evening/weekend hours. Results showed that both facilities scored high in the categories regarding the physical condition of the living areas, as well as the categories concerning the condition of the clients. Greater variability was seen in the data on client and staff behavior. More generally, the results indicate that time-sampling procedures can be used efficiently to collect data on multiple aspects of service delivery for large numbers of individuals.  相似文献   
998.
999.
Three experiments establish the size-weight illusion as a primarily haptic phenomenon, despite its having been more traditionally considered an example of vision influencing haptic processing. Experiment 1 documents, across a broad range of stimulus weights and volumes, the existence of a purely haptic size-weight illusion, equal in strength to the traditional illusion. Experiment 2 demonstrates that haptic volume cues are both sufficient and necessary-for a full-strength illusion. In contrast, visual volume cues are merely sufficient, and produce a relatively weaker effect. Experiment 3 establishes that congenitally blind subjects experience an effect as powerful as that Of blindfolded sighted observers, thus demonstrating that visual imagery is also unnecessary for a robust size-weight illusion. The results are discussed in terms of their implications for both sensory and cognitive theories of the size-weight illusion. Applications of this work to a human factors design and to sensor-based systems for robotic manipulation are also briefly considered.  相似文献   
1000.
When a deaf child is born to hearing parents, a grieving process is initiated in the parents. Unresolved grieving over their child's deafness often makes it difficult for hearing parents to accept the importance of signing, thus increasing the child's problems — further source of grief for these parents. Clinical illustrations are provided of (1) the reciprocal relationship between disruption of the mourning process and disturbance of communication between family members, and (2) the transmission of the dysfunctional relationship between hearing parents and deaf children to the subsequent relationship between the deaf children, when they reach adulthood, and their hearing children.  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