全文获取类型
收费全文 | 2225篇 |
免费 | 41篇 |
国内免费 | 1篇 |
专业分类
教育 | 1475篇 |
科学研究 | 275篇 |
各国文化 | 15篇 |
体育 | 187篇 |
综合类 | 8篇 |
文化理论 | 11篇 |
信息传播 | 296篇 |
出版年
2022年 | 21篇 |
2021年 | 20篇 |
2020年 | 26篇 |
2019年 | 45篇 |
2018年 | 50篇 |
2017年 | 79篇 |
2016年 | 69篇 |
2015年 | 60篇 |
2014年 | 67篇 |
2013年 | 396篇 |
2012年 | 58篇 |
2011年 | 63篇 |
2010年 | 52篇 |
2009年 | 37篇 |
2008年 | 47篇 |
2007年 | 48篇 |
2006年 | 38篇 |
2005年 | 30篇 |
2004年 | 40篇 |
2003年 | 32篇 |
2002年 | 28篇 |
2001年 | 25篇 |
2000年 | 42篇 |
1999年 | 52篇 |
1998年 | 21篇 |
1997年 | 14篇 |
1996年 | 19篇 |
1995年 | 16篇 |
1993年 | 14篇 |
1992年 | 21篇 |
1991年 | 33篇 |
1990年 | 45篇 |
1989年 | 34篇 |
1988年 | 30篇 |
1987年 | 21篇 |
1986年 | 32篇 |
1985年 | 39篇 |
1984年 | 34篇 |
1983年 | 28篇 |
1982年 | 26篇 |
1981年 | 22篇 |
1980年 | 18篇 |
1979年 | 27篇 |
1978年 | 29篇 |
1977年 | 20篇 |
1976年 | 17篇 |
1974年 | 17篇 |
1971年 | 17篇 |
1970年 | 14篇 |
1968年 | 19篇 |
排序方式: 共有2267条查询结果,搜索用时 15 毫秒
191.
A sense of history in science 总被引:1,自引:1,他引:0
I. Bernard Cohen 《Science & Education》1993,2(3):251-277
192.
193.
194.
195.
During the Cold War, Franco’s dictatorship attempted to use technological transfer and nuclear technology to strengthen the geopolitical influence of his Government in Spain. This paper studies this process, with particular reference to the role played by German scientists as advisers to the Spanish nuclear project. 相似文献
196.
I. Rothman 《科学教学研究杂志》1967,5(2):168-173
Scores on a science-related semantic differential test are small but significant predictors of physics and chemistry achievement. 相似文献
197.
198.
R H Orr V M Pings E E Olson I H Pizer 《Bulletin of the Medical Library Association》1968,56(4):380-403
A standardized procedure was developed for eliciting those details of a library's service policies that are important to its users and for recording the data by checking appropriate categories on a form. This inventory procedure covers the entire spectrum of user services and accommodates a wide range of policies. The inventory was originally designed for use by trained interviewers in largescale surveys of academic medical libraries. However, it is also suitable for other kinds of libraries, and the Interview Guide and Checklist can be used for a self-survey by library staff. In addition to survey use, the inventory has a variety of educational, administrative, managerial, and research applications. A method for weighting the categorical inventory data to reflect the relative desirability of different policies makes it possible to calculate scores indicating how a library's policies compare with those of an "optimal" library. An analogous inventory of the services a library provides to other libraries was developed for surveying major backup resources in the medical library system. 相似文献
199.
In this paper, the asymptotic behavior of a generalized Solow model with endogenous labor growth and impulsive perturbations at fixed moments of time is studied. By using the Lyapunov–Razumikhin method sufficient conditions for week uniform asymptotic stability of the solutions are obtained. We also show that the role of impulses in control the behavior of solutions of impulsive models is very important. 相似文献
200.
Schmitt KU Wider D Michel FI Brügger O Gerber H Denoth J 《Sports biomechanics / International Society of Biomechanics in Sports》2012,11(1):57-72
Wrist injuries are frequently observed after falls in snowboarding. In this study, laboratory experiments mimicking forward and backward falls were analysed. In six different falling scenarios, participants self-initiated falls from a static initial position. Eighteen volunteers conducted a total of 741 trials. Measurements were taken for basic parameters describing the kinematics as well as the biomechanical loading during impact, such as impact force, impact acceleration, and velocity. The effective mass affecting the wrist in a fall also was determined. The elbow angle at impact showed a more extended arm in backward falls compared to forward falls, whereas the wrist angle at impact remained similar in forward and backward falls. The study results suggest a new performance standard for wrist guards, indicating the following parameters to characterize an impact: an effective mass acting on one wrist of 3-5 kg, an impact angle of 75 degrees of the forearm relative to the ground, and an impact velocity of 3 m/s. 相似文献