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   51387篇
  免费   815篇
  国内免费   3篇
  52205篇
  2020年   656篇
  2019年   792篇
  2018年   1053篇
  2017年   1115篇
  2016年   1150篇
  2015年   807篇
  2014年   1019篇
  2013年   4338篇
  2012年   1801篇
  2011年   1829篇
  2010年   1177篇
  2009年   1155篇
  2008年   1625篇
  2007年   1635篇
  2006年   1519篇
  2005年   1362篇
  2004年   1261篇
  2003年   1234篇
  2002年   1235篇
  2001年   1384篇
  2000年   1310篇
  1999年   1063篇
  1998年   557篇
  1997年   566篇
  1996年   522篇
  1995年   507篇
  1994年   482篇
  1993年   487篇
  1992年   858篇
  1991年   788篇
  1990年   827篇
  1989年   710篇
  1988年   720篇
  1987年   705篇
  1986年   723篇
  1985年   698篇
  1984年   654篇
  1983年   608篇
  1982年   472篇
  1981年   459篇
  1980年   454篇
  1979年   670篇
  1978年   512篇
  1977年   439篇
  1975年   539篇
  1974年   589篇
  1973年   609篇
  1972年   447篇
  1968年   500篇
  1967年   455篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
171.
The field of infant perceptual development has relied heavily on the preferential-looking and habituation paradigms. Despite the obvious advantages of employing standardized methodologies, there is a need to study how perceptual variables give rise to and guide action beginning in the neonatal period. It is argued here that, in the first 5 months of life, it is important to distinguish reflexive patterns of movement from voluntary and cortically controlled patterns. Some criteria are defined. This paper describes three experiments which utilized movement counters to record developmental changes in the frequency and synchrony of limb movements in infants under 5 months. The results show that there is a general increase in frequency of limb movements from 1 to 5 months, but with a plateau or even a decrease in activity from the middle of the third month to the end of the fourth month. It was also demonstrated that synchrony scores (co-activation) for pairs of limbs showed significant increases from 1 month to 5 months. Finally, in all three experiments the presentation of an attractive toy resulted in suppression of activity. The results of the three experiments are interpreted to measure a gradual increase in cortically controlled movement patterns.  相似文献   
172.
The psychology of knights and knaves   总被引:2,自引:0,他引:2  
L J Rips 《Cognition》1989,31(2):85-116
Knight-knave brain teasers are about a realm in which some people, knights, tell only truths, whereas all others, knaves, tell only lies. For example, suppose person A says, "I am a knight and B is a knight," and person B says, "A is a knave." Is A a knight or a knave? Is B a knight or a knave? In a pilot study, we asked subjects to think aloud while solving problems like these. Their statements suggested that they were making assumptions about the knight/knave status of the characters and drawing deductive inferences from these assumptions to test their consistency. This encouraged us to model the process by means of a simulation based on an earlier natural-deduction theory of reasoning. The model contains a set of deduction rules in the form of productions and a working memory that holds a proof of the correct answer. The greater the number of steps (assumptions and inferences) in the proof, the greater the predicted difficulty of the puzzle. The experiments reported here confirmed this prediction by showing that subjects were more likely to make mistakes (Experiment 1) and take longer to solve (Experiment 2) puzzles associated with a larger number of proof steps.  相似文献   
173.
Topographic electroencephalographic alpha in recovered depressed elderly   总被引:1,自引:0,他引:1  
Late-middle-aged and elderly normal volunteers with past histories of Major Depression according to the Diagnostic and Statistical Manual of Mental Disorders (third edition-revised) criteria were compared with sex- and age-matched control subjects using topographic electroencephalographic (EEG) indices. Healthy, euthymic recovered depressed subjects showed greater alpha amplitudes than controls. Delta, theta, and beta amplitudes did not reliably distinguish the groups. Considered in the context of previous research indicating that actively depressed subjects exhibit elevated EEG alpha compared to controls, these findings raise questions concerning state and trait conceptualizations of depression and EEG alpha.  相似文献   
174.
Shavelson's hierarchical, multifaceted self-concept model (HMFM) has proven useful to educational and psychological researchers. The reliability and factorial validity of a well-known HMFM instrument - the Fleming-Courtney Self-Rating Scales (SRS) - were examined for a sample of 198 Filipino college students. Confirmatory factor analysis compared six structural models. A six-factor, oblique model that included two social factors (Social Acceptance and Social Anxiety) fit the data best, and a second-order factor analysis supported the hierarchical structure of the SRS. The men were significantly higher than the women on three self-concept scales, but the only large effect was for Physical Abilities, consistent with findings in a U.S. college sample. Results provided some support for the utility of both the SRS and HMFM for Filipinos.  相似文献   
175.
The study attempted to replicate and extend the results of an earlier study by Wild and Shapiro (16), establishing the utility of Mosher and Hornsby's (8) 20 Questions Task as a means of differentiating families with schizophrenic patients from those of psychiatrically hospitalized but nonschizophrenic individuals. In the current study, Wild and Shapiro's original design was expanded and revised by (a) diagnosing patients using Research Diagnostic Criteria rather than hospital diagnoses and (b) including families with schizophrenic daughters and/or one-parent families, in addition to intact families with schizophrenic sons. Families were comparable on age, intelligence, and socioeconomic variables. The results failed to replicate those reported by Wild and Shapiro, and indicated that the 20 Questions Task was sensitive to differences in family constellation and offspring gender as well as offspring diagnosis. The findings suggest that forms of familial communication deviance detected with the 20 Questions Task may not be unique to families of schizophrenics, thus highlighting the need to expand research on family communication deviance in families with schizophrenic offspring to families with varied family constellations and characteristics.  相似文献   
176.
Family functioning of 20 alcoholic male veterans and their female partners was assessed in relation to drinking (wet) and abstinent (dry) intervals. Repeated measures analyses performed on the McMaster Family Assessment Device (FAD) indicated that on all 7 scales of the FAD, alcoholics and their mates perceived family functioning to be better during dry than wet periods. In contrast to their alcoholic mates, female partners gave healthier ratings to all FAD scales except Roles in the dry condition and Affective Involvement in the wet condition. According to published cutoff scores for healthy and unhealthy family functioning, alcoholics as a group viewed their wet and dry family functioning as unhealthy, although the female group regarded the family's dry Problem Solving and Behavioral Control as healthy. These findings suggest that the family functioning of alcohol-involved couples is biphasic, oscillating between drinking and abstinent periods.  相似文献   
177.
Little research has been conducted on Loevinger's Washington University Sentence Completion Test of Ego Development in adult psychiatric outpatients. The measure is a promising method of assessing a construct of personality and character functioning that should be useful in research on psychopathology and in choosing treatment modalities. The data presented in this study address the question of the psychometric adequacy of the measure in this segment of the subject population. Specifically, estimates of interrater reliability, internal consistency, and test-retest reliability are presented for a sample of 42 adult outpatients. In addition, the relationship between total protocol ratings and item sum scores is explored.  相似文献   
178.
Adults are able to use a visual target to reduce quiet-standing postural sway (Lee & Lishman, 1975). The present study was designed to determine whether children, under varying postural conditions, are also able to use a visual target to reduce postural sway. A second purpose was to determine the ability of children to visually fixate under different postural conditions. An inability to visually fixate may limit the usefulness of a visual target. The results indicate that, like adults, children are able to reduce sway in the presence of a visual target. Young children are less able than older children and adults to visually fixate. In addition, children show more spontaneous visual saccades in the no-target condition than in the target condition and more saccades in the Romberg stance than in a feet-together stance. The fact that saccades decrease with increasing age, even in the seated, head-stabilized condition, precludes the possibility that increased instability of the young children is the only cause of increased number of saccades.  相似文献   
179.
Children's (N = 28) perceptions of familial relationships were investigated with the Family Environment Scale (FES) and the Network of Relationships Inventory (NRI). The FES assesses overall impressions of the family, and the NRI measures perceptions of individual relationships. Because current family systems theory indicates that positive individual relationships within a dyad (e.g., child-mother) should be related to an overall favorable impression of the family system, we hypothesized that these two instruments should demonstrate convergence on selected dimensions. Results indicated that positive or negative relationships with an individual family member were related to how the child perceived the overall family system, supporting our hypothesis.  相似文献   
180.
Autobiographical memory in a case of multiple personality disorder   总被引:1,自引:0,他引:1  
Previous research on multiple personality disorder (MPD) has been concerned with between-personalities amnesia, and little attention has been paid to within-personality memory function. This study examined the autobiographical memory of a multiple personality patient, I.C., with cueing procedures that have proven useful in previous studies of normal and abnormal memory. Results indicated that I.C. was able to retrieve autobiographical episodes from the recent past, although her performance differed in several respects from that of matched controls. The study also revealed a striking deficit in I.C.'s autobiographical memory for childhood: She was unable to recall a single episode from prior to the age of 10 in response to various retrieval cues, whereas control subjects had no difficulty recalling numerous childhood episodes. This phenomenon of extended childhood amnesia has not been reported previously in studies of MPD.  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