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   6736篇
  免费   68篇
  国内免费   78篇
教育   4578篇
科学研究   1083篇
各国文化   22篇
体育   294篇
综合类   169篇
文化理论   71篇
信息传播   665篇
  2023年   9篇
  2022年   55篇
  2021年   121篇
  2020年   101篇
  2019年   101篇
  2018年   129篇
  2017年   185篇
  2016年   241篇
  2015年   261篇
  2014年   327篇
  2013年   527篇
  2012年   461篇
  2011年   504篇
  2010年   397篇
  2009年   312篇
  2008年   335篇
  2007年   297篇
  2006年   257篇
  2005年   812篇
  2004年   546篇
  2003年   347篇
  2002年   169篇
  2001年   106篇
  2000年   60篇
  1999年   35篇
  1998年   13篇
  1997年   17篇
  1996年   13篇
  1995年   13篇
  1994年   7篇
  1993年   7篇
  1992年   7篇
  1991年   7篇
  1990年   12篇
  1989年   6篇
  1988年   7篇
  1987年   6篇
  1986年   5篇
  1985年   5篇
  1983年   5篇
  1982年   7篇
  1979年   4篇
  1978年   3篇
  1977年   4篇
  1976年   4篇
  1975年   3篇
  1974年   3篇
  1971年   3篇
  1885年   2篇
  1870年   2篇
排序方式: 共有6882条查询结果,搜索用时 15 毫秒
121.
In Grutter vs. Bollinger, the U.S. Supreme Court ruled that the use of race as one factor, among many in admissions decisions is constitutional. It is not known, however, whether future legal opinions will continue to uphold the use of affirmative action policies. Some have argued that class-based preferences can achieve many of the same goals as in affirmative action while being more likely to withstand legal challenges. To date, no empirical studies have been conducted on the potential impact of a class-based admissions policy if implemented at an undergraduate institution. This paper reports on a study at a selective public college and compares a number of outcomes under three admissions models: the original admissions decisions, a purely academic model, and an socio-economic status (SES)-based model. The findings showed that use of the SES-based model would have led to a more academically qualified class than in the original admitted class while maintaining substantially greater student diversity that was found under the academic model. An admissions policy based on preferences for socio-economically disadvantaged applicants appears to hold promise for other colleges and universities with similar institutional and applicant characteristics. The ideas and research design reported in this paper are based on the doctoral dissertation study of the second author, Undergraduate Admissions Models Incorporating Socioeconomic Factors (Johnson, 2000).  相似文献   
122.
Theories of adolescent connectedness suggest that adolescents strive to become connected by engaging with and valuing the people, activities, and worlds in their social ecology. The purpose of this study was to examine the psychometric properties of a measure designed to assess these worlds of connectedness among 320 junior high school students in Taiwan. The subscales and composite scales evidenced satisfactory reliability and concurrent validity. A hypothesized three-factor, higher order structural model of connectedness was cross-validated. Girls were generally more connected than boys. Both connectedness to school and to friends explained more variance in connectedness to self than did family connectedness. There was mixed support for separation-individuation processes. The measure appears promising in terms of future research on adolescent social development in the Asia Pacific.  相似文献   
123.
The first year of a 5 year professional development project for elementary teachers in two mid-western states integrated a bridge of two distinctly different distance education networks (T-1 and fiber optics) to provide science professional development for elementary school teachers in rural communities. Interactive television (ITV), the title given to the distance component, consisted of a series of twenty-four, 2 h presentations by scientists and content specialists. It provided expansion to the science pedagogical content knowledge of the elementary teachers involved. Eighty-five teachers in 38 school districts from the two states completed individual surveys following the final ITV session. Analysis of variance of participants post-session survey scores yielded differences (p < 0.05) on the subscales measuring perceived effectiveness of using distance education for professional development purposes and years of teaching experience. Teachers with over 20 years of classroom experience perceived the use of distance education technologies for science professional development to be more effective than teachers with 16–20 years of classroom experience. These results might suggest another digital divide.  相似文献   
124.
125.
反应级数的确定在化学动力学研究中非常重要,现给出了利用计算机和用微分法确定反应级数的方法.为了使编程的程序简短、高效,采用MATLAB语言作为编程语言.  相似文献   
126.
车联网、无人驾驶等交通领域的科技创新大量涌现,这在一定程度上对交通运输专业学生的专业创新能力培养提出一定的挑战,也创造了一定的机遇。文章以提升学生专业创新能力为目标,通过对学生创新情况的抽样调查和分析,以“交通工程设施设计”课程为例,从教学内容和教学方法两方面进行教学改革探索和实践,以期为新时代背景下的交通设计类课程教学改革提供参考与借鉴。  相似文献   
127.
《心是孤独的猎者》是卡森.麦卡勒斯的名著之一。通过对一个有很多悲微小人物的小镇的描写,麦卡勒斯表现了现代社会中的人的精神孤独感。而其时缓时急、时快时慢的独特叙事方式节奏更体现出其小说的艺术价值。  相似文献   
128.
129.
Luciferase from firefly lantern extract was immobilized on CNBr-activated Sepharose 4B. The kinetic properties of immobilized luciferase were extensively studied. TheK m′ for D-luciferin is 11.9 μmol/L, the optimum pH and temperature for Sepharose-bound enzyme were 7.8 and 25°C respectively. A luminescence fiber optic biosensor, making use of immobilized crude luciferase, was developed for assay of ATP. The peak light intensity was linear with respect to ATP concentration in range of 10−9–10−5 mol/L. A biological application was also demonstrated with the determination of serum ATP from rats bred in low versus normal oxygen environments.  相似文献   
130.
ABSTRACT

Research Findings: Continuity of care is a recommended practice in child care intended to promote secure and supportive relationships between infants and toddlers and their caregivers. Toddlers (= 115) between 12 and 24 months were observed in 30 continuity and 29 noncontinuity classrooms. The average duration of care for toddlers with caregivers was 14 months in the continuity rooms and 5 months in noncontinuity rooms. Toddlers observed in continuity rooms experienced higher levels of interactive involvement with their caregivers and were rated by their caregivers as having fewer problem behaviors compared with the toddlers in noncontinuity rooms. Toddlers in rooms with higher staff–child ratios also experienced more involved caregiving. We did not find evidence that the level of involved caregiving mediated the association between continuity of care and toddlers’ social competence or problem behaviors. Practice or Policy: Continuity of care may be a promising practice for programs that strive to provide high-quality care for infants and toddlers.  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