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   1070篇
  免费   23篇
  国内免费   2篇
教育   837篇
科学研究   43篇
各国文化   12篇
体育   45篇
文化理论   20篇
信息传播   138篇
  2022年   7篇
  2021年   7篇
  2020年   13篇
  2019年   27篇
  2018年   29篇
  2017年   41篇
  2016年   33篇
  2015年   24篇
  2014年   28篇
  2013年   243篇
  2012年   32篇
  2011年   28篇
  2010年   28篇
  2009年   22篇
  2008年   37篇
  2007年   16篇
  2006年   22篇
  2005年   16篇
  2004年   18篇
  2003年   16篇
  2002年   19篇
  2001年   31篇
  2000年   22篇
  1999年   19篇
  1998年   10篇
  1997年   11篇
  1995年   10篇
  1994年   10篇
  1993年   11篇
  1992年   14篇
  1991年   13篇
  1990年   10篇
  1989年   8篇
  1987年   14篇
  1986年   20篇
  1985年   14篇
  1984年   7篇
  1983年   13篇
  1982年   8篇
  1980年   8篇
  1979年   13篇
  1978年   10篇
  1976年   6篇
  1975年   6篇
  1974年   6篇
  1973年   6篇
  1972年   8篇
  1970年   6篇
  1969年   7篇
  1966年   7篇
排序方式: 共有1095条查询结果,搜索用时 18 毫秒
61.
International Journal for the Advancement of Counselling - This content analysis examined assessments available for the screening of sex trafficking to provide professional counselors further...  相似文献   
62.
Science & Education - This article focuses on uncertainty—ways in which scientists recognize and analyze limits in their studies and conclusions. We distinguish uncertainty from...  相似文献   
63.
This meta-analysis examined the relationship between prenatal maternal stress and/or anxiety and the outcomes of children aged 3 months to 9 years. Of the 8754 studies published before June 2021 that were synthesized, 17 conducted in Western countries were included in the meta-analysis (Ntotal = 23,307; Mmales 54%; Methnicity White 77%, Pacific 15%, African American/Black 10%, Middle Eastern 7%, Eastern 8%). Effect sizes ranged from −0.41 to 0.15. A weak negative association was found between prenatal stress and/or anxiety exposure and children's general intellectual development. Associations varied based on the type of exposure. Findings are limited to developed counties and cannot be generalized to low- and middle-income countries. Directions for maternal prenatal intervention and future studies are discussed.  相似文献   
64.
This article reports on analyses of the instructional practices of six middle- and high-school science teachers in the United States who participated in a research-practice partnership that aims to support reform science education goals at scale. All six teachers were well qualified, experienced, and locally successful—respected by students, parents, colleagues, and administrators—but they differed in their success in supporting students' three-dimensional learning. Our goal is to understand how the teachers' instructional practices contributed to their similarities in achieving local success and to differences in enabling students' learning, and to consider the implications of these findings for research-practice partnerships. Data sources included classroom videos supplemented by interviews with teachers and focus students and examples of student work. We also compared students' learning gains by teacher using pre–post assessments that elicited three-dimensional performances. Analyses of classroom videos showed how all six teachers achieved local success—they led effectively managed classrooms, covered the curriculum by teaching almost all unit activities, and assessed students' work in fair and efficient ways. There were important differences, however, in how teachers engaged students in science practices. Teachers in classrooms where students achieved lower learning gains followed a pattern of practice we describe as activity-based teaching, in which students completed investigations and hands-on activities with few opportunities for sensemaking discussions or three-dimensional science performances. Teachers whose students achieved higher learning gains combined the social stability characteristic of local classroom success with more demanding instructional practices associated with scientific sensemaking and cognitive apprenticeship. We conclude with a discussion of implications for research-practice partnerships, highlighting how partnerships need to support all teachers in achieving both local and standards-based success.  相似文献   
65.
Bioluminescence resonance energy transfer (BRET) is a form of Förster resonance energy transfer. BRET has been shown to support lower limits of detection than fluorescence resonance energy transfer (FRET) but, unlike FRET, has not been widely implemented on microfluidic devices for bioanalytical sensing. We recently reported a microscope-based microfluidic system for BRET-based biosensing, using a hybrid, high quantum-efficiency, form of BRET chemistry. This paper reports the first optical fiber-based system for BRET detection on a microfluidic chip, capable of quantifying photon emissions from the low quantum-efficiency BRET2 system. We investigated the effects of varying core diameter and numerical aperture of optical fibers, as well as varying microfluidic channel design and measurement conditions. We optimized the set-up in order to maximize photon counts and minimize the response time. The optimized conditions supported measurement of thrombin activity, with a limit of detection of 20 pM, which is lower than the microscope-based system and more than 20 times lower than concentrations reported to occur in plasma clots.  相似文献   
66.
67.
68.
A mathematical theory is developed for an imagined device termed a “junctor”. A junctor could be used to interconnect two n-terminal networks giving rise to another n-terminal network. Actually a junctor is itself a simple network with three banks of n-terminals internally connected in some fashion by perfectly conducting wires. Adjacency matrices are formulated to analyze various junctors and their current flows. The main problem treated concerns conditions which would ensure that the junctor operation is associative.  相似文献   
69.
70.
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