首页 | 官方网站   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   120183篇
  免费   1904篇
  国内免费   237篇
文化教育   122324篇
  2021年   931篇
  2020年   1682篇
  2019年   2595篇
  2018年   3148篇
  2017年   3414篇
  2016年   3454篇
  2015年   2323篇
  2014年   3190篇
  2013年   27297篇
  2012年   2435篇
  2011年   2817篇
  2010年   2385篇
  2009年   2624篇
  2008年   2439篇
  2007年   2200篇
  2006年   2405篇
  2005年   2403篇
  2004年   3060篇
  2003年   2348篇
  2002年   2122篇
  2001年   2034篇
  2000年   1639篇
  1999年   1488篇
  1998年   1288篇
  1997年   1367篇
  1996年   1575篇
  1995年   1356篇
  1994年   1355篇
  1993年   1345篇
  1992年   1437篇
  1991年   1347篇
  1990年   1372篇
  1989年   1301篇
  1988年   1121篇
  1987年   1088篇
  1986年   1113篇
  1985年   1342篇
  1984年   1189篇
  1983年   1138篇
  1982年   1114篇
  1981年   1029篇
  1980年   981篇
  1979年   1177篇
  1978年   1083篇
  1977年   970篇
  1976年   883篇
  1975年   738篇
  1974年   737篇
  1973年   704篇
  1971年   555篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
Early childhood is a sensitive period for learning and social skill development. The maturation of cerebral regions underlying social processing lays the foundation for later social-emotional competence. This study explored myelin changes in social brain regions and their association with changes in parent-rated social-emotional development in a cohort of 129 children (64 females, 0–36 months, 77 White). Results reveal a steep increase in myelination throughout the social brain in the first 3 years of life that is significantly associated with social-emotional development scores. These findings add knowledge to the emerging picture of social brain development by describing neural underpinnings of human social behavior. They can contribute to identifying age-/stage-appropriate early life factors in this developmental domain.  相似文献   
62.
63.
ABSTRACT

Meta-analytic evidence supports that exercise has benefits for short-term memory (STM) and long-term memory (LTM). However, only three studies with children have tested the differential effects of exercise on STM and LTM. The purpose of this study was to examine the effects of an aerobic fitness test on STM and LTM and to consider the moderating effects of grade level. Children (7–13 years of age) were randomly assigned to either perform an aerobic fitness test before (exercise prior) or after (exercise post) performing the Rey Auditory Verbal Learning Test (RAVLT) to assess memory. Memory was tested again after approximately 24 hours. There were significant differences in memory performance as a function of grade with 4th and 6th graders consistently outperforming 2nd graders. For learning, Day 1 Retention, 24-hr recall, and Day 2 Retention, the exercise prior group performed better than the exercise post group. It is concluded that an aerobic fitness test performed prior to a declarative memory test benefits LTM as compared to when the aerobic fitness test is performed after the memory test.  相似文献   
64.
Tertiary Education and Management - Although they have been developed for a variety of purposes, classification systems for tertiary or postsecondary education institutions offer a foundation for...  相似文献   
65.
ABSTRACT

The present study aimed to provide reference values for lower-limb muscle power assessed during the incremental jump squat (JS) test in elite athletes (i.e., professional athletes competing at international level). We pooled data from all JS tests performed by elite athletes of different sports in two high-performance centres between 2015 and 2019, and computed reference values (i.e., terciles) for mean power (MP), mean propulsive power (MPP), and peak power (PP). Reference values were obtained from 684 elite athletes (458 male and 226 female) of 16 different sports (boxing, judo, karate, fencing, taekwondo, wrestling, basketball, soccer, futsal, handball, rugby union, badminton, tennis, long distance running, triathlon, and sprinting). Significant differences (p < 0.001) were found between male and female athletes for MP (7.47 ± 1.93 and 6.15 ± 1.68 W·Kg?1, respectively), MPP (10.50 ± 2.75 and 8.63 ± 2.43 W·Kg?1), and PP (23.64 ± 6.12 and 19.35 ± 5.49 W·Kg?1). However, the velocity at which these power measures was attained seemed to be independent of sex (~0.95, 1.00 and 2.00 m·s?1 for mean, mean propulsive, and peak velocity, respectively) and homogeneous across different sport disciplines (coefficient of variation <10%). These data can be used to classify athletes’ power capabilities, and the optimum velocity ranges provided here could be useful for training purposes.  相似文献   
66.
When referring to objects, adults package words, sentences, and gestures in ways that shape children's learning. Here, to understand how continuity of reference shapes word learning, an adult taught new words to 4-year-old children (= 120) using either clusters of references to the same object or no sequential references to each object. In three experiments, the adult used a combination of labels and other object references, which provided informative discourse (e.g., This is small and green), neutral discourse (e.g., This is really great), or no verbal discourse. Switching verbal references from one object to another interfered with learning relative to providing clustered references to a particular object, revealing that discontinuity in discourse hinders children's encoding of new words.  相似文献   
67.
The purpose of this study was to test the directionality of influence between reading comprehension (RC) and print exposure (PE), thereby estimating genetic and environmental effects of this relation. The sample consisted of 910 twins in fourth through ninth grades (Mage = 12.33 years, SD = 1.41) from the Florida Twin Project on Reading, Behavior, and Environment. Using direction-of-causation model in a twin design, results supported a direction of influence running from RC to PE. This relation was underpinned by genetic and environmental factors of RC as well as PE. Implications for reading education are discussed.  相似文献   
68.
Previously, research on wishful thinking has found that desires bias older children’s and adults’ predictions during probabilistic reasoning tasks. In this article, we explore wishful thinking in children aged 3- to 10-years-old. Do young children learn to be wishful thinkers? Or do they begin with a wishful thinking bias that is gradually overturned during development? Across five experiments, we compare low- and middle-income United States and Peruvian 3- to 10-year-old children (N = 682). Children were asked to make predictions during games of chance. Across experiments, preschool-aged children from all backgrounds consistently displayed a strong wishful thinking bias. However, the bias declined with age.  相似文献   
69.
70.
Multilevel bifactor item response theory (IRT) models are commonly used to account for features of the data that are related to the sampling and measurement processes used to gather those data. These models conventionally make assumptions about the portions of the data structure that represent these features. Unfortunately, when data violate these models' assumptions but these models are used anyway, incorrect conclusions about the cluster effects could be made and potentially relevant dimensions could go undetected. To address the limitations of these conventional models, a more flexible multilevel bifactor IRT model that does not make these assumptions is presented, and this model is based on the generalized partial credit model. Details of a simulation study demonstrating this model outperforming competing models and showing the consequences of using conventional multilevel bifactor IRT models to analyze data that violate these models' assumptions are reported. Additionally, the model's usefulness is illustrated through the analysis of the Program for International Student Assessment data related to interest in science.  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-23

京公网安备 11010802026262号