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   300篇
  免费   7篇
文化教育   307篇
  2023年   2篇
  2022年   5篇
  2021年   6篇
  2020年   7篇
  2019年   10篇
  2018年   17篇
  2017年   7篇
  2016年   18篇
  2015年   5篇
  2014年   18篇
  2013年   89篇
  2012年   13篇
  2011年   11篇
  2010年   5篇
  2009年   14篇
  2008年   5篇
  2007年   6篇
  2006年   7篇
  2005年   9篇
  2004年   4篇
  2003年   7篇
  2002年   1篇
  2001年   1篇
  2000年   1篇
  1999年   2篇
  1998年   3篇
  1996年   2篇
  1993年   2篇
  1991年   2篇
  1989年   1篇
  1988年   4篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1984年   3篇
  1982年   1篇
  1981年   1篇
  1979年   2篇
  1978年   1篇
  1977年   3篇
  1973年   1篇
  1972年   1篇
  1970年   1篇
  1948年   1篇
  1945年   1篇
  1934年   1篇
  1930年   1篇
  1919年   1篇
  1910年   1篇
排序方式: 共有307条查询结果,搜索用时 397 毫秒
91.
Low-cost physical activity monitors may provide a more accurate measure of physical activity than subjective methods (e.g., self-report) while being less costly than research-grade accelerometers. The present study assessed the validity of a low-cost monitor (Movband 2) to estimate physical activity behavior/intensity. Participants (N = 23, n = 16 female, BMI = 22.9 ± 4.0 kg/m2, age = 21.9 ± 1.6 years) completed four, five-minute treadmill stages (2.0, 3.0, 4.0, 5.0 MPH) while wearing both the Movband and the previously-validated Actigraph monitor. Oxygen consumption (VO2) was recorded during each stage (Laboratory assessment). A subset (= 15, n = 10 female, BMI = 22.2 ± 3.2 kg/m2, age = 21.5 ± 0.8 years) of these participants then wore the two accelerometers for three days (Free-living assessment). During the Laboratory assessment there were strong, significant (= 0.94, p ≤ 0.001) relationships between Movband and Actigraph counts and VO2. During Free-living assessment there was also a strong, significant (= 0.97, p < 0.001) correlation between Movband and Actigraph counts. The low-cost, Movband accelerometer appears to provide a valid assessment of physical activity behavior/intensity.  相似文献   
92.
Merle Jacob 《Minerva》2009,47(4):391-405
The new prominence given to science for economic growth and industry comes with an increased policy focus on the promotion of commodification and commercialization of academic science. This paper posits that this increased interest in commodification is a new steering mechanism for governing science. This is achieved by first outlining what is meant by the commodification of scientific knowledge through reviewing a selection of literatures on the concept of commodification. The paper concludes with a discussion of how commodification functions as a means for governing science.  相似文献   
93.
This study examines the ways single Black mothers contribute to the educational success of their 11th-grade sons, despite the fact that their sons are enrolled in “failing schools.” Data from five interviews and one focus group reveal common characteristics of how single-Black mothers help their sons beat the odds.  相似文献   
94.
95.
96.
This study seeks to shed light on the informal process of knowledge production in criminology and criminal justice by examining acknowledgements in journal publications. Studying the structure of research collaboration among scholars may enhance our understanding of the discipline’s organization. We test hypotheses derived from prior research by analyzing acknowledgements in 786 articles from five journals in criminology and criminal justice over the last five years. As anticipated by the “invisible college” hypothesis, criminology and criminal justice scholarship contains a small group of individuals who receive a disproportionate share of acknowledgements. Additionally, we find that higher ranked and more productive scholars are awarded more acknowledgements than their lower ranked and less productive counterparts. Integrating acknowledgements as an unofficial assessment tool may improve the collective endeavor of contemporary science in our field. Overall, the influence of the “invisible colleagues,” measured by acknowledgements, demonstrates the value of collaboration in the process of knowledge production.  相似文献   
97.
98.
Much has been written about how to evaluate static graphics from the perspective of clarity, ethics, efficiency, and power relations. However, when considering interactive graphics, agency must enter the conversation. This article develops a typology to understand the balance of agency between the designers and users of interactive graphics. The authors use this typology to interrogate 2 contemporary theories of rhetorical agency advanced by Miller and by Herndl and Licona.  相似文献   
99.
Passive particle focusing based on inertial microfluidics was recently introduced as a high-throughput alternative to active focusing methods that require an external force field to manipulate particles. In inertial microfluidics, dominant inertial forces cause particles to move across streamlines and occupy equilibrium positions along the faces of walls in flows through straight micro channels. In this study, we systematically analyzed the addition of secondary Dean forces by introducing curvature and show how randomly distributed particles entering a simple u-shaped curved channel are focused to a fixed lateral position exiting the curvature. We found the lateral particle focusing position to be fixed and largely independent of radius of curvature and whether particles entering the curvature are pre-focused (at equilibrium) or randomly distributed. Unlike focusing in straight channels, where focusing typically is limited to channel cross-sections in the range of particle size to create single focusing point, we report here particle focusing in a large cross-section area (channel aspect ratio 1:10). Furthermore, we describe a simple u-shaped curved channel, with single inlet and four outlets, for filtration applications. We demonstrate continuous focusing and filtration of 10 μm particles (with >90% filtration efficiency) from a suspension mixture at throughputs several orders of magnitude higher than flow through straight channels (volume flow rate of 4.25 ml/min). Finally, as an example of high throughput cell processing application, white blood cells were continuously processed with a filtration efficiency of 78% with maintained high viability. We expect the study will aid in the fundamental understanding of flow through curved channels and open the door for the development of a whole set of bio-analytical applications.  相似文献   
100.
In this paper, we estimate the impact of receiving an NIH postdoctoral training grant on subsequent publications and citations. Our sample consists of all applications for NIH postdoctoral training grants (unsuccessful as well as successful) from 1980 to 2000. Both ordinary least squares and regression discontinuity estimates show that receipt of an NIH postdoctoral fellowship leads to about one additional publication over the next five years, which reflects a 20% increase in research productivity.  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