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   22254篇
  免费   989篇
  国内免费   6篇
  2020年   229篇
  2019年   338篇
  2018年   419篇
  2017年   431篇
  2016年   465篇
  2015年   322篇
  2014年   438篇
  2013年   1996篇
  2012年   723篇
  2011年   794篇
  2010年   483篇
  2009年   516篇
  2008年   664篇
  2007年   706篇
  2006年   646篇
  2005年   568篇
  2004年   586篇
  2003年   527篇
  2002年   535篇
  2001年   550篇
  2000年   620篇
  1999年   447篇
  1998年   293篇
  1997年   238篇
  1996年   257篇
  1995年   247篇
  1994年   224篇
  1992年   357篇
  1991年   345篇
  1990年   344篇
  1989年   324篇
  1988年   311篇
  1987年   275篇
  1986年   292篇
  1985年   318篇
  1984年   250篇
  1983年   254篇
  1982年   228篇
  1981年   217篇
  1979年   299篇
  1978年   258篇
  1977年   213篇
  1975年   260篇
  1974年   280篇
  1973年   312篇
  1972年   259篇
  1971年   231篇
  1968年   263篇
  1967年   246篇
  1966年   220篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
931.
Reports findings from interviews with parents of demographically-comparable groups of highly-stressed urban children with stress-resilient (SR) and stress-affected (SA) outcomes at ages 10-12. SR and SA children were compared on family milieu and child development variables assessed within a developmental framework. Compared to SAs, parents of SRs scored higher on variables reflecting parent perceptions of a nurturant caregiver-child relationship and self-views as effective caregivers, in the context of positive discipline practices, a child's positive early temperament, and support for primary caregivers. A discriminant function analysis identified seven variables that optimally differentiated the groups and correctly classified 86% of the Ss as SR or SA.  相似文献   
932.
Automatic processes in lexical access and spreading activation.   总被引:1,自引:0,他引:1  
The semantic priming effect can be reduced or eliminated depending on how the prime word is processed. The experiments reported here investigate this prime task effect. Two experiments used identity and semantic priming tasks to determine whether the prime word is encoded at a lexical level under letter-search conditions. When the prime task was naming, both identity and semantic priming occurred; however, when a letter-search task was performed on the prime word, only identity priming occurred, thus supporting the argument that the search task affects activation of semantic associates rather than lexical access of the prime word. Another experiment demonstrated that this identity priming was the result of lexical processes rather than of letter-by-letter priming. A cross-modal priming technique demonstrated that the letter-search prime task does not actively suppress activation of semantic associates. The implications of these results for automaticity and for proposed mechanisms of priming are discussed.  相似文献   
933.
The purpose of this study was to isolate possible sources of learning ability differences in distinctive encoding of item-specific and relational information. Two mechanisms postulated as underlying ability group differences were attentional capacity (as inferred from the magnitude and direction of correlations between primary and secondary recall) and resource monitoring strategies (as reflected in measures of selective attention and laterality). In Experiment 1, learning disabled and nondisabled childrens' word recall was compared on dichotic listening recall tasks that included nonorienting instructions, and orienting instructions that directed children's attention toward semantic, phonemic, or structural word features. Disabled children showed lower recall and more diffuse selective attention to word features than nondisabled children. Reciprocity (negative correlations) between targeted and background words within and between ability groups was comparable, except when targeted word features were phonemically organized. Experiment 2 indicated that disabled childrens' cued recall was inferior to that of nondisabled children, even though both ability groups produced comparable symmetrical recall patterns related to ear presentations. Taken together, the results suggest that the locus of disabled childrens' distinctive encoding deficiencies is related to resource monitoring strategies during interhemispheric processing.  相似文献   
934.
Crossing 2 adjacent fingers produces a distorted perception when 2 tactile stimuli are touched to the crossed fingertips. This is because a given pair of fingers has a functional range of action within which spatial perception is correct (uncrossed fingers) and beyond which perceived location of tactile stimuli is wrong (crossed fingers). The present study tested the possibility that this range of action could be modified following a long-lasting crossing. Therefore, the functional range of action of the 2nd and 3rd fingers was tested every month in 6 volunteers who maintained the finger crossing for as long as 6 months. The results show that after a variable period of time the range of action was enlarged such that spatial perception was correct with crossed fingers as well. The perceptual organization of the human hand therefore depends on experience and is not rigidly determined on a genetic basis.  相似文献   
935.
The aim of this study was to assess the validity of the notion that anxiety influences maternal style in monkeys. To this end, we investigated the correlations between measures of the quality of mother-infant relationship and scratching, a behavior pattern that reflects a state of anxiety. The subjects were seven group-living macaque mothers and their infants observed during the first 12 weeks postpartum. Postpartum scratching by the mothers was positively correlated with both maternal possessiveness and maternal warmth, two composite measures of the quality of mother-infant relationship that reflect a possessive and attentive maternal style. Evaluation of the correlations between maternal rank and scratching before and after parturition indicated that interactions with their infants, not those with other group companions, were the main source of anxiety for the mothers. These results support the notion that anxiety influences maternal style in monkeys and suggest that studies aimed at investigating physiological and social correlates of maternal emotionality in nonhuman primates could use scratching as a useful and simple behavioral measure.  相似文献   
936.
Implicit and explicit learning: individual differences and IQ   总被引:7,自引:0,他引:7  
We explored the degree to which individual differences in performance were observed in a group of subjects who worked with two different tasks: one implicit and one explicit. The implicit task was a standard artificial grammar-learning task; the explicit was a series-completion problem-solving task. Substantial individual differences were found between subjects on the explicit task; relatively small individual differences were found on the implicit task. Moreover, performance on the explicit task correlated strongly with intelligence quotient, but performance on the implicit task did not. Data from previous experiments were also found to be in agreement with these results. The findings are presented in the context of a general theory of implicit learning proposed recently by Reber (1989a, in press) that derives from considerations of the evolution of cognitive processes. This evolutionary model argues that unconscious, implicit induction systems are evolutionarily older and antedate conscious, explicit learning processes, and that this antiquity carries with it particular patterns of function that differentiate implicit processes from explicit processes.  相似文献   
937.
Even though in Italy, as in the majority of Mediterranean countries, the increase in suicide rates is not among the highest in Europe, between 1969 and 1989 it showed a sharp upswing (+43% among males and +31% among females). In terms of geographical differences, the regions with the highest suicide rate are the northern ones (up to twice the national average). The age groups with the highest suicide risk are those over 74 years (in 1989 the rate among males over 65 was the highest of all: 31.3 per 100,000). The differences in the between-sexes distribution show that among females over 65 years old the suicide rate rose by 70% between 1974 and 1989, versus 77% for males of the same age. The preliminary epidemiological results of one of two Italian centers are presented. These centers are collaborating with the WHO/EURO Multicenter Study on Parasuicide; parasuicide rates are higher for females than for males (55.9 per 100,000, as against 38.1 for males), while the age group at highest risk is seen to be young women (15-24 years), with a specific rate of 115.6.  相似文献   
938.
The present study employed a prospective design to investigate whether Personality Diagnostic Questionnaire—Revised (PDQ-R) scores and/or Hassles Scale—Revised (HS-R) scores predict changes in Axis I psychopathology levels over 1 month, in a nonclinical sample of young adults. The PDQ-R, HS-R, and Hopkins Symptom Checklist (SCL-90) were administered to a mixed-sex sample of 100 undergraduate students on two occasions separated by 1 month. Hierarchical multiple regression analyses indicated that (1) time 1 PDQ-R composite scores predicted changes in scores on 11 SLC-90 scales; (2) time 1 PDQ-R impairment/distress index scores predicted changes in SCL-90 general symptom index scores; (3) only one of the individual PDQ-R personality disorder subscales—the schizotypal personality disorder subscale—predicted changes in SCL-90 general symptom index scores; (4) HS-R scores predicted changes in scores on 9 SCL-90 scales; and (5) in only 3 of the 27 analyses conducted did the statistical interaction between PDQ-R and HS-R scores predict changes in SCL-90 scores. These findings indicate that personality disorder symptomatology and negative life events may independently predict changes in Axis I psychopathology levels and, thus, support the continued inclusion of Axis II and Axis IV in future versions of the Diagnostic and Statistical Manual of Mental Disorders.  相似文献   
939.
Subjects attempted to identify the occasion on which they first reported particular responses to questions that were asked twice during an experiment on hyphosis and memory 1 week earlier. During this earlier experiment, subjects of high and low hypnotizability had been randomly allocatd to one of two recall test sequences: wake-hypnosis ro wake-wake. Recall improved from the first (R1) to the second test (R2) in a comparable manner for both test sequences, indicating a failure of hypnosis to enhance memory. It is noteworthy that, when later queried about the origins of specific recollections, the majority of subjects exhibited a bias to attribute their responses to R1, regardless of whether hypnosis was used during R2. Moreover, low hypnotizables exposed to the hypnotic procedure and, to a lesser extent, high hypnotizables who recalled both times in the waking condition displayed and exaggerated tendency to overattribute recollections to R1. These data indicate that individuals cannot distinguish between memories retrieved prior to hypnosis and those that occured during hypnosis. Implications for implementing judicial standards regarding hypnosis are discussed.  相似文献   
940.
Some decision analysts recommend reserving their models for careful, complete study of complex problems. Others believe simple problem analyses provide the greatest gains. To clarify these issues, I tested: (1) whether simple published analyses compared to complex ones, produced results as non-intuitive; and (2) whether non-intuitiveness represented analytic gain (or equivalently, intuitive loss). Very limited data also examined (3) the gain from adding model intricacy for a given problem vs. selecting more complex problems for analysis. To assess two non-intuitiveness measures, 75 subjects (33 physicians and 42) non-physicians stated their intuitive preferences in 40 (22 published and 18 unpublished) medical dilemmas. For both physicians and non-physicians, simpler models (those with lees than 30 terminal branches in the decision tree) had about one third the non-intuitiveness of more complex ones. Three tests also supported the premise that analyses outperform intuition, therefore that on average the formers' non-intuitiveness reflects less analytic gain. In addition, for different models of the same problem, tree complexity did not correlate with gain. Thus, simpler trees may not generally gain less because they inadequately describe problems. Instead, simpler analyses may represent simpler problems, with more similar intuitive and formal solutions. If so, these findings may help us avoid some costly but unnecessary simple analyses.  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