全文获取类型
收费全文 | 8964篇 |
免费 | 1390篇 |
国内免费 | 1537篇 |
专业分类
电工技术 | 1384篇 |
技术理论 | 1篇 |
综合类 | 974篇 |
化学工业 | 775篇 |
金属工艺 | 120篇 |
机械仪表 | 495篇 |
建筑科学 | 407篇 |
矿业工程 | 90篇 |
能源动力 | 222篇 |
轻工业 | 203篇 |
水利工程 | 121篇 |
石油天然气 | 415篇 |
武器工业 | 183篇 |
无线电 | 738篇 |
一般工业技术 | 854篇 |
冶金工业 | 190篇 |
原子能技术 | 32篇 |
自动化技术 | 4687篇 |
出版年
2024年 | 52篇 |
2023年 | 206篇 |
2022年 | 214篇 |
2021年 | 296篇 |
2020年 | 365篇 |
2019年 | 404篇 |
2018年 | 319篇 |
2017年 | 371篇 |
2016年 | 453篇 |
2015年 | 401篇 |
2014年 | 503篇 |
2013年 | 734篇 |
2012年 | 554篇 |
2011年 | 638篇 |
2010年 | 465篇 |
2009年 | 527篇 |
2008年 | 528篇 |
2007年 | 616篇 |
2006年 | 544篇 |
2005年 | 477篇 |
2004年 | 422篇 |
2003年 | 360篇 |
2002年 | 343篇 |
2001年 | 322篇 |
2000年 | 273篇 |
1999年 | 275篇 |
1998年 | 214篇 |
1997年 | 196篇 |
1996年 | 174篇 |
1995年 | 148篇 |
1994年 | 111篇 |
1993年 | 80篇 |
1992年 | 83篇 |
1991年 | 66篇 |
1990年 | 43篇 |
1989年 | 25篇 |
1988年 | 21篇 |
1987年 | 10篇 |
1986年 | 12篇 |
1985年 | 12篇 |
1984年 | 12篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 19 毫秒
11.
大系统分散鲁棒容错控制的进展及主要成果 总被引:1,自引:0,他引:1
综述了近20年来关联大系统分散鲁棒容错控制的研究动态及取得的主要成果。说明了统一地研究分散鲁棒容错控制的必要性。在分散控制、鲁棒控制和容错控制研究领域内,分析了各种设计方法的主导思想及实质;指出了这些研究成果的意义与存在的问题。文中着重论述了分散、鲁棒、容错控制研究方法的发展途径。 相似文献
12.
K.D. Do Author Vitae Z.P. Jiang Author Vitae Author Vitae H. Nijmeijer Author Vitae 《Automatica》2004,40(1):117-124
This paper presents a method to design an output-feedback controller that simultaneously solves global asymptotic stabilization and tracking of an underactuated omni-directional intelligent navigator—a spherical underwater vehicle moving in a horizontal plane (i.e. at a constant depth). The vehicle does not have a sway actuator and has only position and orientation measurements available. The control development is based on Lyapunov's direct method, backstepping technique and use of interconnected structure of the vehicle dynamics. Numerical simulations demonstrate the results. 相似文献
13.
14.
Magnus Fredriksson Niels Saabye Ottosen 《International journal for numerical methods in engineering》2004,61(11):1809-1834
An accurate and variationally consistent 4‐node quadrilateral element is introduced where high coarse mesh accuracy and low mesh distortion sensitivity are characteristic qualities, even when incompressibility is approached for plane strain. One‐point quadrature integration procedure is adopted and a new improved stabilization technique is developed. Orthogonality conditions are utilized so that the patch test is satisfied for arbitrary quadrilaterals. Several numerical examples including a convergence rate study are presented which confirm the excellent performance of this element. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
15.
Chuanju Xu 《Journal of scientific computing》2006,27(1-3):495-505
A stabilization method for the spectral element computation of incompressible flow problems is investigated. It is based on a filtering procedure which consists in filtering the velocity field by a spectral vanishing Helmholtz-type operator at each time step. Relationship between this filtering procedure and SVV-stabilization method, introduced recently in [JCP, 2004, 196(2), p680], is established. A number of numerical examples are presented to show the accuracy and stabilization capability of the method. 相似文献
16.
Two-Dimensional Physical and Numerical Modeling of a Pile-Supported Earth Platform over Soft Soil 总被引:1,自引:0,他引:1
This paper focuses on the mechanisms occurring in a granular earth platform over soft ground improved by rigid piles. Two-dimensional physical model experiments were performed using the Schneebeli’s analogical soil to investigate the load transfer mechanisms by arching and the settlement reduction and homogenization. Experimental outputs are compared to results obtained on a numerical model using a plane strain continuum approach. The impact of the constitutive model complexity to simulate the platform material behavior was first assessed, but no large difference was recorded. As far as the proposed model, which takes the main features of the observed behavior satisfactorily into account, the numerical procedure could be validated and the parametric studies extended numerically. Both approaches of this study underlined the main geometrical and geotechnical parameters which should inevitably be taken into account in a simplified design method, namely the capping ratio, the platform height, and the platform material shear strength. 相似文献
17.
In control systems, actuators often have nonlinear characteristics that can not be neglected. For linear systems driven by actuators satisfying the generalized sector condition, a robust state feedback controller synthesis method is proposed to achieve the ultimate boundedness control. The method is based on the linear matrix inequality approach and is easy to apply. As an important special case of the generalized sector condition, the saturation characteristic of actuators is discussed separately, and non‐conservative results are obtained. 相似文献
18.
New technologies such as power electronics have made it possible to change continuously the impedance of a power system not only to control power flow but also to enhance stability. A power system incorporating a variable impedance apparatus such as a variable series capacitor (VSrC) and high-speed phase shifter (HSPS) is called VIPS (Variable Impedance Power System) by the authors. This paper proposes a novel control method of VIPS apparatus such as VSrC and HSPS installed at an interconnecting point for stabilizing inter-area unstable and/or oscillatory modes. The proposed design method of the control system is a kind of hierarchical decentralized control method of a large-scale power system based on a Lyapunov function. Under the proposed control scheme, each subsystem can be stabilized independently by local controllers such as AVR, speed governor and PSS, and then the whole interconnected system can be stabilized by VIPS apparatus taking into account interactions between subsystems. The effectiveness and robustness of the VIPS apparatus control are shown by numerical examples with model systems including a large-scale power system. 相似文献
19.
预测井眼稳定性的力学化学耦合方法 总被引:13,自引:8,他引:5
在井眼力学稳定性评价的基础上,将硬脆性页岩水化后岩石强度等参数的变化规律用于页岩水化前后坍塌压力变化的对比分析,结果表明,地层坍塌压力当量密度随页岩水化程度的增加逐渐升高。给出了预测井眼稳定性的力学化学耦合方法,并将该方法应用于现场生产中,取得了较好的预测效果 相似文献
20.