全文获取类型
收费全文 | 2317篇 |
免费 | 261篇 |
国内免费 | 101篇 |
专业分类
电工技术 | 85篇 |
综合类 | 162篇 |
化学工业 | 167篇 |
金属工艺 | 19篇 |
机械仪表 | 49篇 |
建筑科学 | 95篇 |
矿业工程 | 8篇 |
能源动力 | 66篇 |
轻工业 | 92篇 |
水利工程 | 20篇 |
石油天然气 | 6篇 |
武器工业 | 10篇 |
无线电 | 192篇 |
一般工业技术 | 296篇 |
冶金工业 | 794篇 |
原子能技术 | 21篇 |
自动化技术 | 597篇 |
出版年
2024年 | 8篇 |
2023年 | 17篇 |
2022年 | 23篇 |
2021年 | 36篇 |
2020年 | 76篇 |
2019年 | 78篇 |
2018年 | 83篇 |
2017年 | 65篇 |
2016年 | 87篇 |
2015年 | 72篇 |
2014年 | 122篇 |
2013年 | 151篇 |
2012年 | 97篇 |
2011年 | 142篇 |
2010年 | 131篇 |
2009年 | 145篇 |
2008年 | 149篇 |
2007年 | 134篇 |
2006年 | 115篇 |
2005年 | 111篇 |
2004年 | 94篇 |
2003年 | 118篇 |
2002年 | 101篇 |
2001年 | 96篇 |
2000年 | 44篇 |
1999年 | 32篇 |
1998年 | 23篇 |
1997年 | 20篇 |
1996年 | 14篇 |
1995年 | 12篇 |
1994年 | 11篇 |
1992年 | 13篇 |
1990年 | 7篇 |
1989年 | 8篇 |
1985年 | 5篇 |
1984年 | 8篇 |
1982年 | 11篇 |
1966年 | 9篇 |
1965年 | 13篇 |
1964年 | 18篇 |
1963年 | 15篇 |
1962年 | 6篇 |
1961年 | 18篇 |
1960年 | 18篇 |
1959年 | 13篇 |
1958年 | 11篇 |
1957年 | 13篇 |
1956年 | 13篇 |
1955年 | 18篇 |
1954年 | 9篇 |
排序方式: 共有2679条查询结果,搜索用时 15 毫秒
41.
This paper deals with the problem of designing delayed feedback controllers of master‐slave synchronization for Lur'e systems with time‐variant delay (0≤τ0≤τ(t)≤τm). Through partitioning the intervals [0, τ0] and [τ0, τm], respectively, and choosing two augmented Lyapunov‐Krasovskii functionals(LKFs), two delay‐dependent synchronization criteria are formulated in the form of linear matrix inequalities (LMIs), in which the conservatism can be greatly reduced by thinning the partitioning of delay intervals and employing convex combination. Thus the sufficient conditions can be derived for the existence of delayed feedback controllers, and the controller gain matrices can be achieved by solving the established LMIs. Finally, three numerical examples are given to illustrate the presented synchronization schemes. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society 相似文献
42.
Items made of glass, ceramic, etc. are normally stored in stacks and get damaged during the storage due to the accumulated stress of heaped stock. These items are known as breakable items. Here a multi-item inventory model of breakable items is developed, where demands of the items are stock dependent, breakability rates increase linearly with stock and nonlinearly with time. Due to non-linearity and complexity of the problem, the model is solved numerically and final decisions are made using Genetic Algorithm (GA). In a particular case, model is solved analytically as well as numerically and results are compared. Models are developed with both crisp and uncertain inventory costs. For uncertain inventory costs both fuzzy and stochastic parameters are considered. A chance constrained approach is followed to deal with simultaneous presence of stochastic and fuzzy parameters. Different numerical examples are used to illustrate the problem for different cases. 相似文献
43.
In this paper, the problems of exponential stability and exponential stabilization for linear singularly perturbed stochastic systems with time‐varying delay are investigated. First, an appropriate Lyapunov functional is introduced to establish an improved delay‐dependent stability criterion. By applying free‐weighting matrix technique and by equivalently eliminating time‐varying delay through the idea of convex combination, a less conservative sufficient condition for exponential stability in mean square is obtained in terms of ε‐dependent linear matrix inequalities (LMIs). It is shown that if this set of LMIs for ε=0 are feasible then the system is exponentially stable in mean square for sufficiently small ε?0. Furthermore, it is shown that if a certain matrix variable in this set of LMIs is chosen to be a special form and the resulting LMIs are feasible for ε=0, then the system is ε‐uniformly exponentially stable for all sufficiently small ε?0. Based on the stability criteria, an ε‐independent state‐feedback controller that stabilizes the system for sufficiently small ε?0 is derived. Finally, numerical examples are presented, which show our results are effective and useful. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
44.
This paper revisits the problem of delay‐dependent robust ?∞ filtering design for a class of continuous‐time polytopic linear systems with a time‐varying state delay. Based on a newly developed parameter‐dependent Lyapunov–Krasovskii functional combined with Projection Lemma and an improved free‐weighting matrix technique for delay‐dependent criteria, a new sufficient condition for robust ?∞ performance analysis is first derived and then the filter synthesis is developed by using a simple matrix inequality linearization technique. It is shown that the desired filters can be constructed by solving a set of linear matrix inequalities. Finally, two simulation examples are given to show the effectiveness and less conservatism of the proposed method in comparison with the existing approaches. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
45.
This paper investigates the problem of the absolute stability of Lur'e systems with a time‐varying delay. By considering the relationships among the time‐varying delay, its upper bound, and the difference between them, less conservative delay‐dependent stability criteria are obtained and formulated in terms of linear matrix inequalities, without ignoring any useful terms in the derivative of a Lyapunov–Krasovskii functional. Numerical example shows that the results obtained in this paper are better than the previous results. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
46.
47.
We consider a single machine scheduling problem with resource dependent release times that can be controlled by a non-increasing convex resource consumption function. The objective is to minimize the weighted total resource consumption and sum of job completion times with an initial release time greater than the total processing times. It is known that the problem is polynomially solvable in O(n4) with n the number of jobs. 相似文献
48.
We proved some almost sure limit theorems for standard strongly dependent Gaussian sequences in nonstationary cases under some mild conditions. 相似文献
49.
XU Ou LU ShaoHua & JIAN ShuiSheng Faculty of Information Engineering Guangdong University of Technology Guangzhou China 《中国科学:信息科学(英文版)》2010,(2):390-397
The polarization properties for tilted fiber Bragg gratings (TFBGs) are investigated theoretically based on coupled-mode theory and Mueller matrix method. The expression of wavelength-related polarizationdependent loss (PDL) for TFBGs with different tilt angles is derived and calculated. Simulation results are compared, and the results indicate that the polarization capability of TFBGs with 45° angle is stronger than other TFBGs with smaller angles. The degree of polarization for unpolarized light passing T... 相似文献
50.
相关证据的融合及其在机器人多感觉信息融合中的应用 总被引:5,自引:1,他引:4
D-S证据理论在多信息融合中的应用要求各证据间相互独立,这在很多实际场合中却很难实现。本文简要地阐述了基于D-S证据理论的多传感器信息融合算法,提供了一种基于D-S理论的推广方法以理解决融合信息的相关性问题,并用机器人的力学和热学传感器作实验,对该方法有效性进行了研究。 相似文献