全文获取类型
收费全文 | 10657篇 |
免费 | 1651篇 |
国内免费 | 944篇 |
专业分类
电工技术 | 4056篇 |
综合类 | 1047篇 |
化学工业 | 703篇 |
金属工艺 | 337篇 |
机械仪表 | 483篇 |
建筑科学 | 431篇 |
矿业工程 | 372篇 |
能源动力 | 527篇 |
轻工业 | 91篇 |
水利工程 | 391篇 |
石油天然气 | 1281篇 |
武器工业 | 107篇 |
无线电 | 1040篇 |
一般工业技术 | 906篇 |
冶金工业 | 143篇 |
原子能技术 | 243篇 |
自动化技术 | 1094篇 |
出版年
2024年 | 62篇 |
2023年 | 200篇 |
2022年 | 295篇 |
2021年 | 351篇 |
2020年 | 423篇 |
2019年 | 359篇 |
2018年 | 335篇 |
2017年 | 474篇 |
2016年 | 489篇 |
2015年 | 489篇 |
2014年 | 670篇 |
2013年 | 726篇 |
2012年 | 707篇 |
2011年 | 782篇 |
2010年 | 552篇 |
2009年 | 638篇 |
2008年 | 579篇 |
2007年 | 716篇 |
2006年 | 694篇 |
2005年 | 565篇 |
2004年 | 462篇 |
2003年 | 418篇 |
2002年 | 330篇 |
2001年 | 306篇 |
2000年 | 290篇 |
1999年 | 211篇 |
1998年 | 182篇 |
1997年 | 176篇 |
1996年 | 148篇 |
1995年 | 145篇 |
1994年 | 101篇 |
1993年 | 69篇 |
1992年 | 63篇 |
1991年 | 39篇 |
1990年 | 39篇 |
1989年 | 44篇 |
1988年 | 31篇 |
1987年 | 22篇 |
1986年 | 13篇 |
1985年 | 16篇 |
1984年 | 8篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1974年 | 1篇 |
1959年 | 5篇 |
1955年 | 1篇 |
1951年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
隔直电容在弧焊逆变器中抗偏磁能力的分析 总被引:1,自引:0,他引:1
本文采用状态平均法建立了隔直电容在知式焊接逆变器中抗偏磁的动态模型,并进行了动态分析,为焊接逆变器的设计提供了理论依据。 相似文献
62.
孟国强 《水科学与工程技术》2015,(2)
结合wylie的自由气体离散模型,构建了分段低压输水系统因检修操作导致检修箱涵进气的瞬变流数学模型,并结合实例对计算结果进行了分析。该研究可以为长距离有压输水系统的设计和运行管理提供理论依据和技术支持,同时也为二相流的气泡模拟提供一种可供借鉴的思路和方法。 相似文献
63.
64.
Robust grid‐oriented control of high voltage DC links embedded in an AC transmission system 下载免费PDF全文
Several studies have shown that the way to design controllers for the high‐voltage direct current (HVDC) links impacts the transient behavior of the electric system in which the latter are inserted. This can be exploited to improve the performances of the stability of the power system. In this paper, a robust multivariable control design for the converters of an HVDC link is proposed. It is based on the coordination of the control actions of the HVDC converters and the use of a control model. The latter takes into consideration, in addition to the dynamics that mostly impact the stability of the neighbor zone of the HVDC link, several cases of faulted situations modeled as uncertainties. An H∞ controller allowed us to achieve robustness against such uncertainties. The new controller is tested in comparison with the standard vector control and an optimal linear quadratic controller using the EUROSTAG simulation software (Tractebel Engineering, Brussels, Belgium and Réseau de Transport d'Electricité (RTE) ‐ France) on both academic and realistic large‐scale power systems. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
65.
Semi‐global and global containment control of multi‐agent systems with second‐order dynamics and input saturation 下载免费PDF全文
This paper considers both semi‐global and global containment control for a second‐order multi‐agent system that is composed by a network of identical harmonic oscillators or double integrators with multiple leaders and input saturation. A distributed low gain feedback algorithm is proposed to solve the semi‐global containment control problem for the network whose topology is directed and initial condition is taken from any a priori given bounded set. In particular, by using a parametric Lyapunov equation approach, M‐matrix properties and algebraic graph theory, an upper bound of the low gain parameter is estimated such that the low gain feedback matrix can be analytically determined without involving numerical computation. Furthermore, under the assumption that the induced subgraph formed by the followers is strongly connected and detail balanced, two linear feedback protocols are designed for coupled harmonic oscillators and coupled double integrators, respectively, to asymptotically achieve the global containment control of the network with any initial condition. Finally, numerical examples are given to illustrate the effectiveness of the theoretical results. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
66.
Controller design and analysis for singularly perturbed switched systems with actuator saturation 下载免费PDF全文
This paper investigates the problems of controller design and stability analysis for singularly perturbed switched systems subject to actuator saturation. A set of well‐defined sufficient conditions for the existence of state feedback controllers is proposed, under which the closed‐loop system is locally asymptotically stable for arbitrary switching law as long as the singular perturbation parameter is sufficiently small. With the obtained controller, the estimation problem of stability bound and basin of attraction of the closed‐loop system is reduced to solving a convex optimization problem. A numerical example and a hydraulic servo position system are used to illustrate the obtained results. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
67.
Feng Tyan 《Asian journal of control》2016,18(3):899-919
In this work, the capture region of the general ideal proportional navigation guidance law is analyzed with the following constraints: (i) the target's input acceleration is subject to independent or magnitude saturation, and (ii) the missile's input acceleration is subject to magnitude saturation. In addition to the case of unbounded maneuverability of missile with or without knowing the target acceleration, the necessary and sufficient condition for a bounded maneuvering missile that captures a nonmaneuvering target is also derived. Furthermore, the conditions that result in zero impact velocity are discovered and discussed in some of the cases. The capture regions that cannot be obtained analytically are determined numerically by a powerful classifier, the least square support vector machines. To have the capture region ready for least square support vector machines, all the state variables are transformed into modified polar variables and non‐dimensionalized to reduce the number of independent variables. In order to make the implementation possible in real time, an approximation of the Gaussian radial basis function is adopted to obtain the corresponding nonlinear feature mapping function. Through numerous numerical experiments, the proposed technique is found to be adequate for storing the capture region in an onboard fire control computer. 相似文献
68.
69.
孙扬 《单片机与嵌入式系统应用》2015,(5)
集成电路技术的迅速发展,对电源完整性设计提出了更高的要求,设计者通常通过放置各种电容来降低电源噪声以及应对负载瞬态大电流的需求。讨论了电容技术发展对电源完整性设计带来的影响,同时通过对几种典型电容特性的分析,给出了在电源完整性设计中合理选择使用各种滤波电容的解决方案。 相似文献
70.
Semiglobal stabilization of saturated linear systems via multiple parametric Lyapunov equations 下载免费PDF全文
This paper investigates the problem of semiglobal stabilization with guaranteed flexible pole placement for saturated linear systems. To retain the advantages of the parametric Lyapunov equation, matrix‐partitioning idea is used to derive a new pole shift lemma. Starting from system matrix transformations, a recursive algorithm is proposed to shift every eigenvalue of a linear system separately without mode decomposition in each step. A new method introducing various parameters to every Lyapunov equation in each step is presented. As an application, the semiglobal stabilization with guaranteed flexible pole placement for saturated linear systems can be achieved by this method. Finally, its effectiveness and advantages are demonstrated via a simulation example. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献