全文获取类型
收费全文 | 42639篇 |
免费 | 668篇 |
国内免费 | 28篇 |
专业分类
教育 | 30419篇 |
科学研究 | 3676篇 |
各国文化 | 458篇 |
体育 | 3664篇 |
综合类 | 18篇 |
文化理论 | 363篇 |
信息传播 | 4737篇 |
出版年
2021年 | 441篇 |
2020年 | 678篇 |
2019年 | 1044篇 |
2018年 | 1410篇 |
2017年 | 1367篇 |
2016年 | 1232篇 |
2015年 | 747篇 |
2014年 | 1092篇 |
2013年 | 8142篇 |
2012年 | 1010篇 |
2011年 | 1075篇 |
2010年 | 807篇 |
2009年 | 854篇 |
2008年 | 937篇 |
2007年 | 861篇 |
2006年 | 777篇 |
2005年 | 702篇 |
2004年 | 702篇 |
2003年 | 605篇 |
2002年 | 621篇 |
2001年 | 810篇 |
2000年 | 804篇 |
1999年 | 699篇 |
1998年 | 432篇 |
1997年 | 428篇 |
1996年 | 502篇 |
1995年 | 449篇 |
1994年 | 403篇 |
1993年 | 394篇 |
1992年 | 584篇 |
1991年 | 593篇 |
1990年 | 577篇 |
1989年 | 602篇 |
1988年 | 538篇 |
1987年 | 560篇 |
1986年 | 536篇 |
1985年 | 610篇 |
1984年 | 493篇 |
1983年 | 474篇 |
1982年 | 402篇 |
1981年 | 378篇 |
1980年 | 387篇 |
1979年 | 555篇 |
1978年 | 407篇 |
1977年 | 373篇 |
1976年 | 328篇 |
1975年 | 292篇 |
1974年 | 306篇 |
1973年 | 282篇 |
1971年 | 294篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
961.
Veenstra R Lindenberg S Zijlstra BJ De Winter AF Verhulst FC Ormel J 《Child development》2007,78(6):1843-1854
For this study, information on Who Bullies Who was collected from 54 school classes with 918 children (M age = 11) and 13,606 dyadic relations. Bullying and victimization were viewed separately from the point of view of the bully and the victim. The two perspectives were highly complementary. The probability of a bully-victim relationship was higher if the bully was more dominant than the victim, and if the victim was more vulnerable than the bully and more rejected by the class. In a bully-victim dyad, boys were more often the bullies. There was no finding of sex effect for victimization. Liking reduced and disliking increased the probability of a bully-victim relationship. 相似文献
962.
Marital conflict and conduct problems in Children of Twins 总被引:3,自引:0,他引:3
Harden KP Turkheimer E Emery RE D'Onofrio BM Slutske WS Heath AC Martin NG 《Child development》2007,78(1):1-18
The Children-of-Twins design was used to test whether associations between marital conflict frequency and conduct problems can be replicated within the children of discordant twin pairs. A sample of 2,051 children (age 14-39 years) of 1,045 twins was used to estimate the genetic and environmental influences on marital conflict and determine whether genetic or environmental selection processes underlie the observed association between marital conflict and conduct problems. Results indicate that genetic and nonshared environmental factors influence the risk of marital conflict. Furthermore, genetic influences mediated the association between marital conflict frequency and conduct problems. These results highlight the need for quasiexperimental designs in investigations of intergenerational associations. 相似文献
963.
Vaughan Van Hecke A Mundy PC Acra CF Block JJ Delgado CE Parlade MV Meyer JA Neal AR Pomares YB 《Child development》2007,78(1):53-69
Infant joint attention has been observed to be related to social-emotional outcomes in at-risk children. To address whether this relation is also evident in typically developing children, 52 children were tested at 12, 15, 24, and 30 months to examine associations between infant joint attention and social outcomes. Twelve-month initiating and responding to joint attention were related to 30-month social competence and externalizing behavior, even when accounting for 15-month temperament ratings, 24-month cognition and language, and demographic variables. These results suggest that, in addition to associations with language and cognition, infant joint attention reflects robust aspects of development that are related to individual differences in the emergence of social and behavioral competence in childhood. 相似文献
964.
Do infants use past linguistic information to interpret an ambiguous request for an object? When infants in this research were shown 2 objects, and asked for 1 with an indefinite request (e.g., "Can you get it for me?"), both 15- and 18-month-olds used the speaker's previous reference to an absent object to interpret the request. The 18-month-olds did so even when the request was made after a 2.5-min delay. When the request was made by a person who did not participate in the conversation, the infants did not use the previous verbal information. These results demonstrate infants' ability to use language as a source of information in ambiguous contexts and indicate an early appreciation of the shared nature of conversation. 相似文献
965.
The longitudinal development of the intraindividual coupling between academic achievement, interest, and self-concept of ability (SCA) was analyzed in a sample of approximately 1,000 children between grades 1 and 12 (ages 6-17). Across all calculated indexes, the average level of coupling was positive. Individuals generally felt competent and interested in domains where they achieve well, and were interested in domains where they perceive their personal strengths. The degree of coupling was the highest between interest and SCA and the lowest between interest and achievement. For all indexes, evidence for an increase in coupling across time was found. Female gender was related to a lower level of coupling. There was evidence for a positive effect of conscientiousness on the amount of coupling. 相似文献
966.
The objective of the study was to better understand the perceptions and needs of multigenerational Deaf adults related to mental health services. A survey sampled participants who were between 20 and 85 years old and Deaf. Questions were developed to identify the perspectives of Deaf adults related to the availability of mental health services, preferences for these services, and current utilization of services. Participants were grouped into age (years) categories: young adult (18-34), middle adult (35-54), older adult (55-65), and oldest (66-). Category response trends were examined using chi-square analysis. The analysis showed significant differences in the preferences and utilization of mental health care. These data also suggested preferences for service delivery. These data indicate areas of importance related to the development of programs and services for Deaf adults and to indicate where funding for services would be best utilized. 相似文献
967.
Friedman WJ 《Child development》2007,78(5):1472-1491
In two studies of knowledge about the properties and processes of memory for the times of past events, 178 children from 5 through 13 years of age and 40 adults answered questions about how they would remember times on different scales, how temporal memory is affected by retention interval, and the usefulness of different methods. The adults showed quite accurate knowledge about the main properties of memory for time and the processes that underlie it. Different properties and processes were first understood at ages ranging from 8 years to 12 years or later. Knowledge of the roles of reconstruction and impressions of temporal distances appear well after children use them to remember the times of events. 相似文献
968.
Two experiments examined whether 18-month-olds learn from emotions directed to a third party. Infants watched an adult perform actions on objects, and an Emoter expressed Anger or Neutral affect toward the adult in response to her actions. The Emoter then became neutral and infants were given access to the objects. Infants' actions were influenced by their memory of the Emoter's affect. Moreover, infants' actions varied as a function of whether they were currently in the Emoter's visual field. If the previously angry Emoter was absent (Experiment 1) or turned her back (Experiment 2), infants did not use the prior emotion to regulate their behavior. Infants learn from emotional eavesdropping, and their subsequent behavior depends on the Emoter's orientation toward them. 相似文献
969.
Why are hyperactivity and academic achievement related? 总被引:1,自引:0,他引:1
Although a negative association between hyperactivity and academic achievement is well documented, little is known about the genetic and/or environmental mechanisms responsible for the association. The present study explored links between parent and teacher ratings of hyperactive behavior problems and teacher-assessed achievement in a sample of 1,876 twin pairs (mean age 7.04 years). The results did not differ across rater, nor were there significant differences between males or females or for twins in the same or different classrooms. Hyperactivity was significantly correlated with achievement. Multivariate model-fitting analyses revealed significant genetic and nonshared environmental covariance between the two phenotypes. In addition, bivariate heritabilities were substantial, indicating that the phenotypic correlations between hyperactivity and achievement were largely mediated by genetic influences. 相似文献
970.
Kohlberg's (1966) hypothesis that the attainment of gender constancy motivates children to attend to gender norms was reevaluated by examining these links in relation to age. Ninety-four 3- to 7-year-old children were interviewed to assess whether and how constancy mediates age-related changes in gender-related beliefs. As expected, results indicated a general pattern of an increase in stereotype knowledge, the importance and positive evaluation of one's own gender category, and rigidity of beliefs between the ages of 3 and 5. Moreover, the stability phase, rather than full constancy, mediated some of these relations. After age 5, rigidity generally decreased with age, with relations primarily mediated by consistency. 相似文献