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   8526篇
  免费   135篇
  国内免费   192篇
  2018年   21篇
  2017年   27篇
  2016年   26篇
  2015年   37篇
  2014年   29篇
  2013年   37篇
  2012年   730篇
  2011年   822篇
  2010年   210篇
  2009年   104篇
  2008年   628篇
  2007年   652篇
  2006年   552篇
  2005年   494篇
  2004年   447篇
  2003年   369篇
  2002年   374篇
  2001年   256篇
  2000年   282篇
  1999年   149篇
  1998年   52篇
  1997年   25篇
  1996年   47篇
  1995年   30篇
  1994年   73篇
  1993年   96篇
  1992年   91篇
  1991年   100篇
  1990年   90篇
  1989年   97篇
  1988年   109篇
  1987年   122篇
  1986年   86篇
  1985年   113篇
  1984年   105篇
  1983年   135篇
  1982年   85篇
  1981年   89篇
  1980年   79篇
  1979年   82篇
  1978年   66篇
  1966年   48篇
  1965年   131篇
  1964年   104篇
  1963年   127篇
  1962年   54篇
  1958年   83篇
  1957年   75篇
  1956年   46篇
  1953年   16篇
排序方式: 共有8853条查询结果,搜索用时 15 毫秒
921.
Humans show a global advantage when processing hierarchical visual patterns, and they detect the global level of stimulus structure more accurately and faster than the local level in several stimulus contexts. By contrast, capuchins (Cebus apella) and other monkey species show a strong local advantage. A key factor which, if manipulated, could cause an inversion of this effect in monkeys is still to be found. In this study, we examined whether it was possible to induce attention allocation to global and local levels of perceptual analysis in capuchin monkeys and if by doing so, their local dominance could be reversed. We manipulated attentional bias using a matching-to-sample (MTS) task where the proportion of trials requiring global and local processing varied between conditions. The monkeys were compared with humans tested with the same paradigm. Monkeys showed a local advantage in the local bias condition but a global advantage in the global bias condition. The role of attention in processing was confined to the local trials in a first phase of testing but extended to both local and global trials in the course of task practice. Humans exhibited an overall global dominance and an effect of attentional bias on the speed of processing of the global and local level of the stimuli. These results indicate a role for attention in the processing of hierarchical stimuli in monkeys and are discussed in relation to the extent to which they can explain the differences between capuchin monkeys and humans observed in this and other studies.  相似文献   
922.
The action-based model of dissonance and recent advances in neuroscience suggest that commitment to action should cause greater relative left frontal cortical activity. Two experiments were conducted in which electroencephalographic activity was recorded following commitment to action, operationalized with a perceived choice manipulation. Perceived high as compared to low choice to engage in the action, regardless of whether it was counterattitudinal or proattitudinal, caused greater relative left frontal cortical activity. Moreover, perceived high as compared to low choice caused attitudes to be more consistent with the action. These results broaden the theoretical reach of the action-based model by suggesting that similar neural and motivational processes are involved in attitudinal responses to counterattitudinal and proattitudinal commitments.  相似文献   
923.
Eye movements of 30 4-month-olds were tracked as infants viewed animals and vehicles in “natural” scenes and, for comparison, in homogeneous “experimental” scenes. Infants showed equivalent looking time preferences for natural and experimental scenes overall, but fixated natural scenes and objects in natural scenes more than experimental scenes and objects in experimental scenes and shifted fixations between objects and contexts more in natural than in experimental scenes. The findings show how infants treat objects and contexts in natural scenes and suggest that they treat more commonly used experimental scenes differently.  相似文献   
924.

Background

An infant's early environment has an important influence on their development. For example, the sensitivity and warmth of a mother's responses towards her infant is associated with the infant's later socio-emotional development. However, it is less clear whether maternal responses are associated with the infant's later cognitive development.

Method

We used data from a large UK cohort study to investigate the association between non-verbal maternal responses and later infant development and IQ. Maternal responses were rated at 12 months during an observed mother–infant interaction. Infant development was assessed using the Griffiths scales at 18 months and IQ at 4 years was assessed using the Wechsler Preschool and Primary Scale of Intelligence (WPPSI). Data on the infant's developmental level at 6 months (prior to the maternal response ratings) was also available. The complete case sample comprised 732 mother–infant pairs.

Results

There was evidence for an association between positive maternal responses and infant development at 18 months. After adjusting for infant developmental level at 6 months and other confounders, we found a difference of 0.25 standard deviations (coef 2.0, 95% CI (0.8–3.2), p = 0.002) on the Griffiths scales between infant's whose mothers showed positive compared to neutral non-verbal responses at 12 months. However, an association between positive maternal responses and IQ at 4 years diminished following adjustment for maternal educational attainment.

Conclusion

The results provide evidence that positive maternal responses are associated with improved development in infants at 18 months. However, the association between maternal response and IQ at 4 years may be explained by higher educational attainment in mothers who show positive responses. Future studies are needed to explore the influence of maternal responses on different aspects of infant development as well as the role of maternal factors such as education.  相似文献   
925.

Objective

This study examined the contributions of maternal bids for joint attention, relationship quality, and infant characteristics, to individual differences in infants’ parallel and joint attention.

Method

Fifty-two 10-month-olds and their mothers were assessed in order to investigate concurrent predictors of infant parallel attention, responding to joint attention, and initiating joint attention.

Results

Parallel attention was predicted by infants’ higher mental development, low expression of negative emotionality, and maternal entertaining behaviors. Responding to joint attention was marginally predicted by total maternal bids for joint attention. Initiating joint attention was predicted by the infants’ low expression of negative emotionality, as well as marginally predicted by fewer maternal teaching behaviors.

Conclusion

These results further the understanding of the factors influencing infant parallel as well as joint attention.  相似文献   
926.
The aim of this study was to analyze the extent to which the relations and the stability of the neonatal behaviour and the infant behaviour at both 4 and 12 months could be used to predict the infant temperament at 6 years. Seventy-two full-term, normal-weight, healthy children were followed from 3 days postpartum to 6 years. Neonatal behaviour at 3 and 30 days was assessed using the Neonatal Behaviour Assessment Scale (NBAS), behaviour at 4 and 12 months was assessed using the Infant Behaviour Record (IBR) from the Bayley Scales for Infant Development (BSID) and temperament at 6 years was assessed using the Dimensions of Temperament Survey-Revised (DOTS-R). Negative and positive affectivity and attention were the factors extracted from the behaviours of the IBR. Our results showed a low/moderate correlation between neonatal behaviour on the one hand and behaviour at 4 and 12 months and temperament at 6 years on the other hand. The motor performance, orientation and ANS stability of the neonate at 3 and 30 days were predictors of positive and negative affectivity at 4 months. State regulation and ANS stability at 3 days were predictors of negative affectivity and attention respectively at 12 months. Negative affectivity at 12 months and endurance at 30 days were predictors of general activity and persistence/attention at 6 years. Also, an inverse relation was found between state regulation at 30 days and general activity at 6 years, and a positive relation was found between attention at 4 months and persistence/attention at 6 years. We conclude that neonatal behaviour and behaviour in the first year of life are good predictors of temperament at 6 years and that early negative affectivity has an important role on infant temperament development.  相似文献   
927.
The study examined the responses of typically developing infants to the distress of another, prior to and following the transition to the second year. Infants’ responses to maternal simulations of distress and to a peer distress videotape were observed from 8 to 16 months, using an accelerated longitudinal design (overall n = 37). Modest levels of affective and cognitive empathy for another in distress were already evident before the second year, and increased gradually (and not always significantly) across the transition to the second year. Prosocial behavior was rare in the first year and increased substantially during the second year. Self-distress reactions were rare overall. Individual differences in cognitive and affective empathy assessed in the first year, particularly at 10-months, predicted the levels of prosocial behavior observed in the second year. No gender differences were found. Theoretical implications and future research directions are discussed.  相似文献   
928.
To foveate a visual target, subjects usually execute a primary hypometric saccade (S1) bringing the target in perifoveal vision, followed by a corrective saccade (S2) or by more than one S2. It is still debated to what extent these S2 are pre-programmed or dependent only on post-saccadic retinal error. To answer this question, we used a visually-triggered saccade task in which target position and target visibility were manipulated. In one-third of the trials, the target was slightly displaced at S1 onset (so-called double step paradigm) and was maintained until the end of S1, until the start of the first S2 or until the end of the trial. Experiments took place in two visual environments: in the dark and in a dimly lit room with a visible random square background. The results showed that S2 were less accurate for shortest target durations. The duration of post-saccadic visual integration thus appears as the main factor responsible for corrective saccade accuracy. We also found that the visual context modulates primary saccade accuracy, especially for the most hypometric subjects. These findings suggest that the saccadic system is sensitive to the visual properties of the environment and uses different strategies to maintain final gaze accuracy.  相似文献   
929.
This paper presents the Spanish version of the Spence Children Anxiety Scale (SCAS), a rating scale for children and adolescents assessing anxiety disorders as they appear in the DSM-IV. SCAS scores were subjected to confirmatory factor analyses in a sample of 1671 children 10 to 17 years old. Results supported the proposed structure of six interrelated scales. This structure is completely invariant (except for means) in boys and girls and across age groups. Overall, girls scored slightly higher than boys. The relationship of SCAS scores with the child's age was nonexistent or very low and negative. The least frequent anxiety problems among children and adolescents were panic attacks and agoraphobia. Problems that most frequently presented extreme high scores were obsessive-compulsive disorder and social phobia. It is concluded that the Spanish version of the SCAS can confidently be used in the assessment of anxiety disorders in children.  相似文献   
930.
We present a study that investigates changes in the acquisition and development of morphological awareness in children from 5 to 7 years old. This investigation was carried out on three separate occasions over two academic years, in which morphological awareness was assessed according to two levels. The data indicate an increase in the morphological awareness development from the kindergarten to primary education, verifying the acquisition in the first instance of the morphological judgment level and secondly, of morphological production level. It also generates a pattern of acquisition of the various parameters that make up morphology.  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