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   8976篇
  免费   165篇
  国内免费   3篇
  2019年   64篇
  2018年   198篇
  2017年   170篇
  2016年   270篇
  2015年   160篇
  2014年   106篇
  2013年   522篇
  2012年   381篇
  2011年   403篇
  2010年   112篇
  2009年   123篇
  2008年   199篇
  2007年   177篇
  2006年   183篇
  2005年   1452篇
  2004年   760篇
  2003年   579篇
  2002年   275篇
  2001年   107篇
  2000年   75篇
  1999年   107篇
  1998年   62篇
  1997年   56篇
  1996年   64篇
  1995年   56篇
  1994年   67篇
  1993年   65篇
  1992年   72篇
  1991年   105篇
  1990年   109篇
  1989年   87篇
  1988年   81篇
  1987年   96篇
  1986年   82篇
  1985年   86篇
  1984年   102篇
  1983年   71篇
  1982年   73篇
  1981年   69篇
  1979年   96篇
  1978年   58篇
  1977年   78篇
  1976年   75篇
  1975年   85篇
  1974年   97篇
  1973年   100篇
  1972年   64篇
  1971年   59篇
  1968年   52篇
  1966年   60篇
排序方式: 共有9144条查询结果,搜索用时 15 毫秒
21.
Twenty-six suicide attempters, 9 to 18 years of age, were compared with 725 nonattempters on measures of school achievement, educational goals, socioeconomic status, and depression. As has been found in studies using clinical samples, suicide attempters in our communitybased sample had significantly lower school achievement than nonattempters. The relationship between attempted suicide and low school achievement seemed to be explained by the effects of depression. Lower-SES youth tended to be more likely to attempt suicide than higher-SES youths. However, SES appeared to have little effect on the relationship between attempted suicide and school achievement. Results also suggest that children of mothers with low educational goals for them may be more at risk for attempted suicide than youths whose mothers have higher educational goals for their children.This research was supported by the National Institute of Mental Health, Grant No. MH36971.  相似文献   
22.
Wistar rats of three age groups were tested in an automated tunnel-maze system of variable geometry to investigate whether changes in spontaneous locomotor activity and in learning and memory develop differentially or in a correlated fashion as a function of age. Senescent (30 months) as well as mature-adult (17 months) rats showed an age-correlated decline of locomotor activity as compared to the mature-young (5 months) group. Both working-memory (measured as within-trial arm discrimination performance) and reference-memory (measured as avoidance of "blind alley" visits) were severely affected in the senescent group, whereas the middle-aged animals suffered only from a working-memory deficit. The findings provide evidence that locomotor deficits do not necessarily interfere in the assessment of age-related changes in cognitive performance. Furthermore the results support the hypothesis that working and reference memory have different underlying physiological correlates and that these neuronal systems are differentially affected by the aging process.  相似文献   
23.
24.
25.
Observations on three children with neurolisteriosis (one case of meningitis, two cases of meningoencephalitis, each Serovar 4 b), show that even after the neonatal period, listeriosis must not be ignored in the process of diagnosis and therapy. It is the bacteriological examination of the cerebrospinal fluid, together with the blood culture, and not clinical symptoms and serology that guarantee a timely diagnosis and therapy (ampicillin and gentamicin).  相似文献   
26.
Sleep in the dove Zenaida asiatica   总被引:1,自引:0,他引:1  
Electrographic and behavioral observations were made in five adult birds of the genus Zenaida asiatica. Five different vigilance states were quantitated: (1) Active waking (Aw) was characterized by constant behavioral activity; the nuchal electromyogram was tonically active with bursts associated to movements. The electroencephalographic pattern was low voltage and high frequency. (2) Quiet waking (Qw) was characterized by diminished behavioral activity and the EEG pattern was similar to that of Aw. (3) Drowsiness (D) was characterized by behavioral calm. Frequency of cerebral activity diminished progressively, but there were short periods of desynchronization corresponding to brief awakenings. (4) Slow wave sleep (SWS); during this period there was behavioral rest and EEG pattern of continuous slow waves and the nuchal EMG was tonically reduced. Spindles of sleep were not observed. (5) Paradoxical sleep (SP), behaviorally characterized by phasic manifestations consisting of noddings originated by rapid falling down of head and bursts of rapid eye movements. EEG activity was like that of waking state. EMG activity was maintained at the same level as during SWS but sometimes it decreased lightly. Total atonie was not observed. Sleep percentages were higher when recordings were done during the nocturnal period.  相似文献   
27.
28.
29.
The authors examined characteristics of Finnish mothers (N = 924) who use hostile child-rearing practices (i.e., they ignore the child, are punitive and irritable, and perceive the child as a burden), practices that have been shown (R?ikk?nen & Keltikangas-J?rvinen, 1992) to predispose children to Type A behavior. The results of this study indicate that two factors--Type A behavior in the mothers and the mothers' sociodemographic background (low occupational status, low educational level and young age)--increase the probability of the mothers' treating their children in a hostile manner. Also, the mothers of boys in this study reported more hostile child-rearing practices than the mothers of girls did.  相似文献   
30.
Psychological compensation: a theoretical framework.   总被引:1,自引:0,他引:1  
The 2 main objectives of this article are to review a variety of literatures in which the concept of compensation is used and to integrate the results of this review into a general framework of compensation. The review focuses on 4 domains of psychological inquiry: compensation for sensory handicaps, cognitive deficits, interpersonal losses, and brain injury. In the proposed framework, underlying dimensions and 4 basic steps in the progression of compensatory behavior are distinguished. The latter include origins, mechanisms, forms, and consequences. Finally, we describe ways in which researchers in particular domains can benefit from the global, process-oriented framework we propose. For most of the areas of compensation research reviewed, investigators can profit from a consideration of a broader selection of dimensions, additional steps in the process, alternative outcomes, and both objective and subjective assessment procedures.  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