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   14403篇
  免费   200篇
  国内免费   12篇
教育   9762篇
科学研究   1296篇
各国文化   158篇
体育   1538篇
综合类   24篇
文化理论   105篇
信息传播   1732篇
  2021年   111篇
  2020年   217篇
  2019年   311篇
  2018年   357篇
  2017年   430篇
  2016年   380篇
  2015年   245篇
  2014年   328篇
  2013年   2687篇
  2012年   286篇
  2011年   330篇
  2010年   256篇
  2009年   287篇
  2008年   269篇
  2007年   262篇
  2006年   249篇
  2005年   230篇
  2004年   473篇
  2003年   363篇
  2002年   388篇
  2001年   251篇
  2000年   266篇
  1999年   208篇
  1998年   100篇
  1997年   130篇
  1996年   156篇
  1995年   139篇
  1994年   129篇
  1993年   118篇
  1992年   177篇
  1991年   170篇
  1990年   156篇
  1989年   199篇
  1988年   168篇
  1987年   194篇
  1986年   158篇
  1985年   210篇
  1984年   172篇
  1983年   155篇
  1982年   139篇
  1981年   107篇
  1980年   99篇
  1979年   161篇
  1978年   129篇
  1977年   106篇
  1976年   128篇
  1975年   94篇
  1974年   111篇
  1973年   84篇
  1971年   99篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
This study examined the effects of social influences in the lives of an ethnically diverse sample of fifth through eighth grade students with and without learning disabilities (LD) using survey data and academic achievement scores collected in 19 Chicago public schools from 1993–1997. Similarities and differences in student perceptions of school, family, and peer group contexts were examined. In addition, longitudinal data were analyzed using hierarchical linear modeling (HLM) to identify contextual influences on changes in student reading achievement over time. Comparisons of student responses confirm and extend existing findings in the literature concerning the perceptions of students with LD of their social environments. In particular, having a learning disability was associated with consistent, mostly negative, effects on social relations across the contexts of students’ lives, regardless of gender, race, grade, and socioeconomic status. In addition, student perceptions of their friendship groups were found to have small, but significant, effects on their growth in reading achievement over the course of middle school. While students with and without LD had somewhat different views of their social contexts, the processes working within these environments appeared to affect their reading achievement in similar ways. The results suggest that careful attention should be paid to the social contexts of students’ lives when planning academic interventions.  相似文献   
992.
993.
The U.S. government technical report is a primary means by which the results of federally funded research and development (R&D) are transferred to the U.S. aerospace industry. However, little is known about this information product in terms of its actual use, importance, and value in the transfer of federally funded R&D. Little is also known about the intermediary-based system that is used to transfer the results of federally funded R&D to the U.S. aerospace industry. To help establish a body of knowledge, the U.S. government technical report is being investigated as part of the NASA/DoD Aerospace Knowledge Diffusion Research Project. In this article, we summarize the literature on the U.S. government technical report and present the results of a survey of U.S. aerospace engineers and scientists that solicited their opinions concerning the format of NASA Langley Research Center (LaRC)-authored technical reports. To learn more about the preferences of U.S. aerospace engineers and scientists concerning the format of NASA LaRC-authored technical reports, we surveyed 133 report producers (i.e., authors) and 137 report users in March–April 1996. Questions covered such topics as: (a) the order in which report components are read; (b) components used to determine if a report would be read; (c) those components that could be deleted; (d) the placement of such components as the symbols list; (e) the desirability of a table of contents; (f) the format of reference citations; (g) column layout and right margin treatment; and (h) writing style in terms of person and voice. Mail (self-reported) surveys were used to collect the data. The response rates for report producers (i.e., authors) was 68% and for users, was 62%.  相似文献   
994.
Converging evidence from a number of neuroimaging studies, including our own, suggest that fluent word identification in reading is related to the functional integrity of two left hemisphere posterior systems: a temporo-parietal system and a ventral occipito-temporal system. These posterior systems are functionally disrupted in developmental dyslexia. Reading disabled, relative to nonimpaired, readers demonstrate heightened reliance on both inferior frontal and right hemisphere posterior regions, presumably in compensation for the LH posterior difficulties. We propose a neurobiological account suggesting that for normally developing readers the temporo-parietal system predominates at first, and is associated with aspects of processing critical in learning to integrate orthography with phonological and lexical-semantic features of printed words. The occipito-temporal system, by contrast, constitutes a fast, late-developing, word-identification system that underlies fluent word recognition in skilled readers.  相似文献   
995.
996.
Six Danish male cross-country skiers were studied during the end-of-summer and winter seasons. Their maximal oxygen uptake was measured while running on a treadmill and using a ski ergometer incorporating the double-poling technique. Maximal oxygen uptake during treadmill running and double-poling was correlated with performance, expressed as a ranking score during 10 ski races. The tests were undertaken in September, December and April. Upper body maximal oxygen uptake increased 5.8% from September to December, decreasing to 2.3% above the September level in April. Upper body work output (2 min at maximal intensity) increased 11.8% from September to December (P less than 0.05). The relationship between upper body and leg maximal oxygen uptake--the upper body/leg ratio--was 89.4% in September. In four skiers, both treadmill and upper body tests were undertaken on each test occasion. The upper body/leg ratio changed from 87.7% in September to 95.7% in December. In April, the ratio was 91.0%. The maximal oxygen uptake measured using the ski ergometer during double-poling was significantly correlated with performance (P less than 0.05). It is concluded that the upper body ski ergometer can be used in the evaluation of elite cross-country skiers.  相似文献   
997.
998.
999.
1000.
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