全文获取类型
收费全文 | 585篇 |
免费 | 14篇 |
国内免费 | 1篇 |
专业分类
教育 | 366篇 |
科学研究 | 144篇 |
各国文化 | 6篇 |
体育 | 29篇 |
综合类 | 4篇 |
文化理论 | 5篇 |
信息传播 | 46篇 |
出版年
2023年 | 11篇 |
2022年 | 10篇 |
2021年 | 25篇 |
2020年 | 15篇 |
2019年 | 31篇 |
2018年 | 37篇 |
2017年 | 48篇 |
2016年 | 26篇 |
2015年 | 26篇 |
2014年 | 41篇 |
2013年 | 77篇 |
2012年 | 40篇 |
2011年 | 22篇 |
2010年 | 30篇 |
2009年 | 22篇 |
2008年 | 28篇 |
2007年 | 16篇 |
2006年 | 10篇 |
2005年 | 11篇 |
2004年 | 10篇 |
2003年 | 10篇 |
2002年 | 11篇 |
2001年 | 6篇 |
2000年 | 7篇 |
1999年 | 2篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1970年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有600条查询结果,搜索用时 15 毫秒
41.
Ali Karami-Mollaee Hamed Tirandaz Oscar Barambones 《Journal of The Franklin Institute》2019,356(8):4577-4600
Mismatched uncertainty and chattering appear as two challenges in sliding mode control. To overcome the problem of mismatched uncertainty, multiple sliding surfaces with virtual inputs are proposed. Accordingly, we have proposed two new methods based on designed neural observer: sliding mode control (SMC) and dynamic sliding mode control (DSMC) methods. Although, the proposed SMC can significantly cope with the mismatched uncertainties, but it suffers from chattering phenomenon. The chattering problem can be removed in DSMC, because an integrator is placed before the system. This results in increased number of the system states. This new state can be identified with the proposed neural observer. Note that in both proposed approaches, the robust performance (invariance property) of system is reserved, even in the presence of mismatch uncertainties. Then, to have a valid comparison the proposed DSMC is also designed using loop transfer recovery observer (LTRO). This comparison shows the good performance of the DSMC based neural networks. Moreover, the upper bound of uncertainties is not used in SMC and DSMC controllers and also in the neural observer and LTRO, which is important in practical implementation. Finally, comparing the equations, one can see the simplicity of DSMC in concept and also in realization. 相似文献
42.
Syed Ali Ajwad Tomas Ménard Emmanuel Moulay Michael Defoort Patrick Coirault 《Journal of The Franklin Institute》2019,356(16):10031-10057
This paper deals with the leader-following consensus problem of multi-agent systems with the consideration that each agent can only transmit its position state to the neighbors at irregular discrete sampling times. In the proposed algorithm, a continuous-discrete time observer is designed for the continuous estimation of both position and velocity from the discrete position information of the neighbors. These estimated states are then used for designing a continuous control law which solves the leader-following consensus problem. Moreover, the dynamics of the leader is not fixed and can be controlled through an external input. The stability analysis has been carried out by employing the Lyapunov approach which provides sufficient conditions to tune the parameters according to the maximum allowable sampling period. The developed algorithm has been simulated and then tested on an actual multi-robot system consisting of three differential drive wheeled robots. Both simulation and hardware results validate the effectiveness of the control algorithm. 相似文献
43.
从十多年证券市场的发展历程来看,股权筹资处于主导地位,而债权筹资不足.近几年衍生金融工具筹资有了一些新的发展,如可转债、权证、资产支持证券等,为上市公司筹资提供了更多可供选择的筹资渠道体系.2000年以后股权筹资金额逐年下降,债权筹资逐年上升,资本结构逐步趋于合理.全流通后,上市公司的筹资市场环境将发生巨大的变化,企业的筹资成本与风险也会发生很大的变化,股权筹资稀释控制权的后果将会显现出来,负债筹资的优势也会更加明显.上市公司应充分利用不同筹资工具的优势和特色,降低企业的资金成本和筹资风险,优化资本结构. 相似文献
44.
团学活动在高职生关键能力培养中的拓展作用 总被引:1,自引:0,他引:1
吴阿莉 《石家庄铁路职业技术学院学报》2008,7(3)
在比较、分析关键能力内涵的基础上,指出应很好地重视和发挥团学活动在高职生关键能力培养中作用,并结合实际提出通过团学活动培养和提高高职生关键能力应遵循的四条原则。 相似文献
45.
Ali Shoukot Sarker Md Fouad Hossain Islam M. Saiful Islam Md Kabirul Al Mahmud Rafi 《Tertiary Education and Management》2021,27(2):91-106
Tertiary Education and Management - This study examines how students from rural areas in Bangladesh face particular challenges in adapting to university dormitories in urban areas. There has been... 相似文献
46.
Changes in the world of work as well as demographic shifts toward a more diverse college population and workforce require changes in the way career counseling is provided on college campuses. The authors propose using a narrative group counseling approach to serve college and university students from various cultural backgrounds. Through this approach, students develop their own career/life stories, incorporating their cultural values, family and community considerations, and life roles. 相似文献
47.
Mehmet Ali Ozturk Charles Debelak 《International Review of Education/Internationale Zeitschrift für Erziehungswissenschaft/Revue internationale l'éducation》2008,54(1):83-97
The present article scrutinizes “the unique American vision of childhood” (UAVC) as a phenomenon undermining high academic expectations and good work ethics, and in turn, contributing to the generally low academic achievement of U.S. students compared to their counterparts in other advanced countries. It starts with a definition of UAVC, followed by a discussion of how influential it has been. The article goes on to state three reasons why UAVC is troublesome and misleading, especially in an era of global competition. Excuses devised by the proponents for UAVC’s adverse effects are also revealed. The article ends with recommendations for future research and a conclusion elaborating on the consequences of UAVC and the likelihood that other countries might adopt a similar mentality. 相似文献
48.
49.
Garrison Yunkyoung Ali Saba Rasheed Lin Ching-Lan Rosaline Kim Ji Youn Cindy Heshmati Sara 《International Journal for Educational and Vocational Guidance》2021,21(3):589-606
International Journal for Educational and Vocational Guidance - The present study discusses a pilot intervention for youth in a predominantly Latinx rural community in the U.S. The intervention... 相似文献
50.
Syed Shamil B.Sc. Ph.D. C.Chem. M.R.S.C. M.I.F.S.T. Gordon G. Birch B.Sc. Ph.D. D.Sc. F.R.C.S. F.I.F.S.T. 《Endeavour》1990,14(4)
Of all the senses, that of taste is perhaps the hardest to define and quantify and elucidation of the underlying mechanisms is unrespondingly difficult. This article describes a conceptual model — at the molecular level — for the four basic taste modalities, using apparent specific volume as a fundamental parameter. It also considers possible practical applications. 相似文献