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   42888篇
  免费   905篇
  国内免费   5篇
  43798篇
  2020年   443篇
  2019年   505篇
  2018年   681篇
  2017年   694篇
  2016年   811篇
  2015年   569篇
  2014年   644篇
  2013年   2932篇
  2012年   1250篇
  2011年   1246篇
  2010年   792篇
  2009年   741篇
  2008年   1093篇
  2007年   1077篇
  2006年   949篇
  2005年   885篇
  2004年   844篇
  2003年   782篇
  2002年   783篇
  2001年   1313篇
  2000年   1255篇
  1999年   924篇
  1998年   431篇
  1996年   371篇
  1992年   887篇
  1991年   824篇
  1990年   831篇
  1989年   734篇
  1988年   725篇
  1987年   698篇
  1986年   724篇
  1985年   810篇
  1984年   610篇
  1983年   565篇
  1982年   386篇
  1981年   379篇
  1979年   703篇
  1978年   434篇
  1977年   433篇
  1976年   423篇
  1975年   597篇
  1974年   681篇
  1973年   724篇
  1972年   623篇
  1971年   592篇
  1970年   580篇
  1969年   569篇
  1968年   755篇
  1967年   665篇
  1966年   597篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
871.
Compulsive procrastination: some self-reported characteristics   总被引:1,自引:0,他引:1  
In Sample 1, 46 procrastinators compared with 52 nonprocrastinators claimed lower self-esteem, greater public self-consciousness and social anxiety, and a stronger tendency toward self-handicapping. In Sample 2, 48 procrastinators compared with 54 nonprocrastinators reported a weaker tendency toward seeking self-identity information but a stronger tendency toward a diffuse-identity style, yet there were no significant differences in verbal and abstract thinking abilities. Further research must provide evidence for persistent procrastination as a personality disorder that includes anxiety, avoidance, and a fear of evaluation of ability.  相似文献   
872.
By using a self-management program, a 25-yr.-old white male was able to decrease the amount of junk food and beverage consumed while increasing the amount of healthier food and beverage ingested during evening snacks. This change was evident at 6 wk. and at a 6-mo. follow-up. Factors contributing to this success were discussed.  相似文献   
873.
A previous study (Tr?ster, 1989) showed that nonhandicapped persons preferred a physically handicapped interaction partner to a nonhandicapped partner in an attributionally unambiguous situation. In order to test whether this "sympathy effect of physical handicap" is based on tendencies of impression management, 48 female subjects had to choose to sit next to either a physically handicapped or nonhandicapped female interaction partner in order to view a film together. Attributional ambiguity was varied by either confounding the choice of an interaction partner with a second, socially acceptable alternative (attributionally ambiguous situation: a choice between two films) or not confounding it (attributionally unambiguous situation: no choice between films). Public responsibility was manipulated by informing the subjects about their freedom to choose where they wished to sit either in public (public responsibility) or in private (no public responsibility). The results supported the impression management hypothesis: The handicapped interaction partner (in a wheelchair) was only preferred when the subjects had to anticipate that observers would deduce a preference of the chosen partner from the subjects' choices because of the attributionally unambiguous situation and the public announcement of their freedom of choice. Results suggest that the nonhandicapped strive to exhibit positive and nondiscriminative behavior toward the handicapped in order to avoid creating a disadvantageous impression in an observer.  相似文献   
874.
Fifty-five families of chronically offending delinquents were randomly assigned to parent-training treatment or to service traditionally provided by the juvenile court and community. The families in the parent-training group received an average of 44.8 hours of professional contact (23.3 hours of which were phone contacts), and each control group family received treatment estimated at more than 50 hours on the average. Comparisons of police contact data at baseline and subsequent years for the two groups showed that subjects in both groups demonstrated reduced rates of offending during the followup years. The finding most relevant was significant treatment-by-time effect for offense rates, with most of this effect accounted for by a greater reduction in serious crimes for the experimental group during the treatment year, and a similar reduction of the community control group occurring in the first of three followup years. These early decrements in offense rates persisted during followup for both groups. Throughout the study, boys in the experimental group spent significantly less time in institutional settings than did boys in the control group. Parent training had a significant impact, but the reduction in offending was produced at very high emotional cost to staff. Although it is clear that this population requires substantial treatment resources, this study underscores the need for more work on prevention.Research for this paper was supported by grant MH 37938 from the Center for Studies of Antisocial and Violent Behavior, National Institute of Mental Health (NIMH), U.S. Public Health Service (PHS). The writing was supported in part by grants MH 17126 and MH 37940 from the same Center, grant DA 05304 from the National Institute of Drug Abuse, U.S. PHS., and grant MH 38730 from the Child and Adolescent Disorders Research Branch, NIMH, U.S. PHS. The authors gratefully acknowledge the enduring commitment of the treatment staff that made this study possible: Patricia Chamberlain, Marion Forgatch, and Kate Kavanagh.  相似文献   
875.
Early lexical development in children with focal brain injury   总被引:4,自引:0,他引:4  
Early lexical development in 27 children with focal brain injury was studied cross-sectionally and longitudinally. Data were obtained from children between 12 and 35 months of age who acquired their lesion prenatally or within the first 6 months of life. Results for the group as a whole provide clear evidence for delays in lexical comprehension and production, and for a larger number of comprehension/production dissociations than would be expected by chance. In addition, a significant number of children were observed having unusual difficulty mastering predication and/or using an atypically high proportion of closed class words (suggesting reliance on holistic/formulaic speech). Analyses by lesion type revealed no effect of lesion size. Analyses according to side of lesion revealed that children with right-hemisphere damage produced a higher proportion of closed class words, suggesting heavy reliance on well-practiced but under-analyzed speech formulae. Children with left-hemisphere damage were slightly better in comprehension than children with right-hemisphere damage. In addition, left posterior lesions were associated with greater delays in expressive language, and delays were more protracted in children with left posterior damage. No differential effects of left posterior damage were found for lexical comprehension.  相似文献   
876.
Tested a preventive intervention in which peer telephone dyads were developed for low-income, community-living, elderly women with low perceived social support. After an initial assessment, respondents were randomly assigned to either an assessment-only control or received 10 weeks of friendly staff telephone contact. After a second assessment, participants receiving the staff contact were randomly assigned to continue that contact or were paired in dyads to continue phone contact with one another. Dependent variables were measures of perceived social support, morale, depression, and loneliness. All groups, particularly the staff contact group, showed some improvement in mental health scores over time, but there were no significant differences between intervention groups, or between intervention and assessment-only control groups. The results suggest that participation in the study and in personal assessment interviews at home were probably morale enhancing, and that additional telephone contact did not significantly add to that effect. Evidence also indicates that, in this sample, low perceived family support was significantly related to poor mental health, so it is possible that a program designed to increase friend support may have been the wrong intervention.  相似文献   
877.
Task dynamics corresponding to rhythmic movements emerge from interactions among dynamical resources composed of the musculature, the link segments, and the nervous and circulatory systems. This article investigated whether perturbations of interlimb coordination might be effect over circulatory and nervous elements. Stiffness of wrist-pendulums oscillated at a common tempo and at 180 degrees relative phase was perturbed through the use of tonic activity about an ankle. Left and right stiffnesses, the common period, and the phase relation all changed. Stiffnesses increased with ankle torque in proportion to the wrist's inertial load. Despite different changes in stiffness at the two wrists, isochrony was preserved. The stability was shown to be consistent with the proportionality of changes in stiffness to the inertial loads. The phase departed from antiphase in proportion to the asymmetry of inertial loads. The size of departures decreased with increasing ankle torque. An account was developed in terms of muscular, circulatory, and nervous functions.  相似文献   
878.
Trajectory and kinematics of drawing movements are mutually constrained by functional relationships that reduce the degrees of freedom of the hand-arm system. Previous investigations of these relationships are extended here by considering their development in children between 5 and 12 years of age. Performances in a simple motor task--the continuous tracing of elliptic trajectories--demonstrate that both the phenomenon of isochrony (increase of the average movement velocity with the linear extent of the trajectory) and the so-called two-thirds power law (relation between tangential velocity and curvature) are qualitatively present already at the age of 5. The quantitative aspects of these regularities evolve with age, however, and steady-state adult performance is not attained even by the oldest children. The power-law formalism developed in previous reports is generalized to encompass these developmental aspects of the control of movement.  相似文献   
879.
Two experiments report the effects of generating a concurrent position expectancy and form expectancy. Ss were precued to a stimulus position where 1 target shape was most probable, and they made a speeded 2-choice response to the orientation of the displayed shape. Response time (RT) was faster for an expected position than an unexpected position and faster for a likely shape than for an unlikely shape. This replicates the work of Lambert and Hockey (1986). It was also observed, however, that when a stimulus appeared at an unexpected position where 2 shapes were equally improbable, RT was slower for the shape that had been likely rather than unlikely at the cued position. This finding is incompatible with the probability-matching hypothesis of Lambert and Hockey. The data support a hierarchical-expectancy model of attentional selectivity.  相似文献   
880.
Four experiments used the visual search paradigm to examine feature integration mechanisms. Reaction time to determine the presence or absence of a conjunctive target is relatively fast and exhaustive for low-density displays. Search rate is slow and self-terminating for high-density displays. Density effects do not arise when the target is defined by a unique feature. Two mechanisms are proposed for feature integration. A fast mechanism integrates features on the basis of coarse location information coded with the initial registration of the features. This coarse location mechanism requires that display items be spaced apart. A second, slower mechanism is used when objects are clumped together. The 2-mechanism hypothesis provides a resolution to conflicting findings in the visual search and illusory-conjunction literature. A possible interpretation of the findings with a single guided search mechanism for feature integration is also discussed.  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