全文获取类型
收费全文 | 546篇 |
免费 | 8篇 |
专业分类
教育 | 438篇 |
科学研究 | 26篇 |
各国文化 | 7篇 |
体育 | 25篇 |
文化理论 | 4篇 |
信息传播 | 54篇 |
出版年
2023年 | 5篇 |
2022年 | 3篇 |
2021年 | 8篇 |
2020年 | 4篇 |
2019年 | 20篇 |
2018年 | 18篇 |
2017年 | 23篇 |
2016年 | 17篇 |
2015年 | 12篇 |
2014年 | 14篇 |
2013年 | 127篇 |
2012年 | 14篇 |
2011年 | 12篇 |
2010年 | 13篇 |
2009年 | 9篇 |
2008年 | 11篇 |
2007年 | 15篇 |
2006年 | 11篇 |
2005年 | 13篇 |
2004年 | 7篇 |
2003年 | 11篇 |
2002年 | 10篇 |
2001年 | 9篇 |
2000年 | 9篇 |
1999年 | 10篇 |
1998年 | 7篇 |
1996年 | 4篇 |
1995年 | 8篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1992年 | 10篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1985年 | 5篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1980年 | 4篇 |
1979年 | 7篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1976年 | 4篇 |
1974年 | 4篇 |
1971年 | 7篇 |
1969年 | 3篇 |
1868年 | 3篇 |
1866年 | 2篇 |
1865年 | 3篇 |
排序方式: 共有554条查询结果,搜索用时 15 毫秒
31.
32.
33.
34.
35.
Technological agglomeration and the emergence of clusters and networks in nanotechnology 总被引:3,自引:0,他引:3
Research and development at the nanoscale requires a large degree of integration, from convergence of research disciplines in new fields of enquiry to new linkages between start-ups, regional actors and research facilities. Based on the analysis of two clusters in nanotechnologies (MESA+ (Twente) and other centres in The Netherlands and Minatec in Grenoble in France), the paper discusses the phenomenon of technological agglomeration: co-located scientific and technological fields associated to coordinated technology platforms to some extent actively shaped by institutional entrepreneurs. Such co-location and coordination are probably a pre-requisite for the emergence of strong nanoclusters. 相似文献
36.
37.
38.
This paper examines the earnings, work patterns, and work histories of individuals employed in the field of dance using data from a survey of graduates of the Five College Dance Department. The respondents to our survey include not only those currently working in dance, but also some who never entered the profession and many others who entered but later left the field. We find that graduate education in dance, age, and prior dance experience are highly correlated with employment in the field of dance. Our findings are similar to those of other studies on artists, in showing that the returns to dance are low and that many of those employed in dance rely on non-dance jobs to supplement their dance earnings. 相似文献
39.
Many scientists and coaches are interested in mechanical power produced during cycling, and use Schoberer Rad Me\technik (SRM)
bicycle power cranks to obtain this data. However, it has been expensive and difficult to calibrate SRM cranks, causing much
of the collected data to be unreliable. We present a static method, derived from first principles, for obtaining a calibration
factor for SRM cranks.
A known mass and lever arm (chainring of a known diameter) are used to apply a known torque load to the instrument in four
positions, and the output frequencies are used to calculate the calibration factor in Hz/Nm. The reproducibility of this method
is ±0.01 Hz/Nm, which is acceptable for the application of the instrument, which is measurement of mechanical power application
by cyclists at the crank.
The method is reliable, inexpensive, and easy to set up, and will allow higher confidence in data collected using SRM power
cranks. We recommend calibration of the power meter once every six months because of the measured drift of the calibration
factor over time. 相似文献
40.