全文获取类型
收费全文 | 5038篇 |
免费 | 846篇 |
国内免费 | 802篇 |
专业分类
电工技术 | 1205篇 |
综合类 | 721篇 |
化学工业 | 166篇 |
金属工艺 | 78篇 |
机械仪表 | 464篇 |
建筑科学 | 61篇 |
矿业工程 | 29篇 |
能源动力 | 143篇 |
轻工业 | 25篇 |
水利工程 | 39篇 |
石油天然气 | 33篇 |
武器工业 | 118篇 |
无线电 | 388篇 |
一般工业技术 | 348篇 |
冶金工业 | 51篇 |
原子能技术 | 105篇 |
自动化技术 | 2712篇 |
出版年
2024年 | 31篇 |
2023年 | 168篇 |
2022年 | 162篇 |
2021年 | 231篇 |
2020年 | 296篇 |
2019年 | 347篇 |
2018年 | 222篇 |
2017年 | 300篇 |
2016年 | 313篇 |
2015年 | 291篇 |
2014年 | 319篇 |
2013年 | 437篇 |
2012年 | 365篇 |
2011年 | 366篇 |
2010年 | 258篇 |
2009年 | 306篇 |
2008年 | 262篇 |
2007年 | 283篇 |
2006年 | 257篇 |
2005年 | 210篇 |
2004年 | 178篇 |
2003年 | 137篇 |
2002年 | 127篇 |
2001年 | 107篇 |
2000年 | 90篇 |
1999年 | 78篇 |
1998年 | 61篇 |
1997年 | 60篇 |
1996年 | 73篇 |
1995年 | 63篇 |
1994年 | 48篇 |
1993年 | 38篇 |
1992年 | 56篇 |
1991年 | 30篇 |
1990年 | 28篇 |
1989年 | 15篇 |
1988年 | 18篇 |
1987年 | 5篇 |
1986年 | 6篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 7篇 |
1981年 | 7篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1959年 | 1篇 |
1954年 | 1篇 |
1951年 | 1篇 |
排序方式: 共有6686条查询结果,搜索用时 31 毫秒
1.
Felipe A. Perdomo Siti H. Khalit Claire S. Adjiman Amparo Galindo George Jackson 《American Institute of Chemical Engineers》2021,67(3):e17194
The SAFT-γ Mie group-contribution equation of state is used to represent the fluid-phase behavior of aqueous solutions of a variety of linear, branched, and cyclic amines. New group interactions are developed in order to model the mixtures of interest, including the like and unlike interactions between alkyl primary, secondary, and tertiary amine groups (NH2, NH, N), cyclic secondary and tertiary amine groups (cNH, cN), and cyclic methine-amine groups (cCHNH, cCHN) with water (H2O). The group-interaction parameters are estimated from appropriate experimental thermodynamic data for pure amines and selected mixtures. By taking advantage of the group-contribution nature of the method, one can describe the fluid-phase behavior of mixtures of molecules comprising those groups over broad ranges of temperature, pressure, and composition. A number of aqueous solutions of amines are studied including linear, branched aliphatic, and cyclic amines. Liquid–liquid equilibria (LLE) bounded by lower critical solution temperatures (LCSTs) have been reported experimentally and are reproduced here with the SAFT-γ Mie approach. The main feature of the approach is the ability not only to represent accurately the experimental data employed in the parameter estimation, but also to predict the vapor–liquid, liquid–liquid, and vapor–liquid–liquid equilibria, and LCSTs with the same set of parameters. Pure compound and binary phase diagrams of diverse types of amines and their aqueous solutions are assessed in order to demonstrate the main features of the thermodynamic and fluid-phase behavior. 相似文献
2.
To design robust interval observers for uncertain continuous‐time linear systems, a new set‐integration approach is proposed to compute trajectory tubes for the estimation error. Because this approach, the order‐preserving condition on the dynamics of the estimation error is no longer required. Therefore, synthesis methods can be used to compute observer gains that reduce the impact of the system uncertainties on the accuracy of the estimated state enclosures. The performance of the proposed approach is showcased through illustrative numerical examples. 相似文献
3.
Sanjeev Kumar Pandey S. L. Patil Praveen V. Pol S. B. Phadke 《International Journal of Electronics》2020,107(10):1682-1703
ABSTRACT In this paper, two control schemes for boost converters affected by uncertainties in input voltage and load are proposed. The boost converter dynamics is redefined in terms of new state variables to facilitate the use of a disturbance observer that can estimate matched and unmatched disturbances. A sliding surface, which is new in the context of boost converters, is proposed to enable tracking and regulation of output voltage without requiring measurement of input voltage and load current. The stability of the overall system including the disturbance observer, the sliding variable and the output is proved. The performance of the schemes is assessed for regulation of output voltage and tracking of reference voltage by simulation as well as experimentation in which various types of uncertainties and various types of reference voltages are considered. 相似文献
4.
M. Brøns 《Dynamical Systems: An International Journal》2018,33(1):136-158
A canard explosion is the dramatic change of period and amplitude of a limit cycle of a system of nonlinear ODEs in a very narrow interval of the bifurcation parameter. It occurs in slow–fast systems and is well understood in singular perturbation problems where a small parameter epsilon defines the time-scale separation. We present an iterative algorithm for the determination of the canard explosion point which can be applied for a general slow–fast system without an explicit small parameter. We also present assumptions under which the algorithm gives accurate estimates of the canard explosion point. Finally, we apply the algorithm to the van der Pol equations, a Templator model for a self-replicating system and a model for intracellular calcium oscillations with no explicit small parameters and obtain very good agreement with results from numerical simulations. 相似文献
5.
6.
This paper investigates the prescribed performance attitude control problem for flexible spacecraft subject to external disturbances and actuator constraints. By using a new performance function and an error transformation, the attitude control system is transformed into an error system which will be kept bounded to ensure expected dynamic and steady-state responses. Compared with the commonly used performance function, the modified one has an explicit prespecified terminal time which determines the maximum convergence time of the attitude control system. A modal observer and a disturbance observer are designed to deal with the flexible vibration and disturbances, respectively. Furthermore, when considering actuator saturation, an improved control strategy is developed with an auxiliary system utilized to compensate the saturation. The stability of the closed-loop system is analyzed by Lyapunov theory. Simulation results show the effectiveness and performance of the proposed methods. 相似文献
7.
Hande Fendoğlu Canan Bozkaya Münevver Tezer-Sezgin 《Computers & Mathematics with Applications》2019,77(2):374-388
The unsteady magnetohydrodynamic (MHD) flow of a viscous, incompressible and electrically conducting fluid in a rectangular duct with a perturbed boundary, is investigated. A small boundary perturbation is applied on the upper wall of the duct which is encountered in the visualization of the blood flow in constricted arteries. The MHD equations which are coupled in the velocity and the induced magnetic field are solved with no-slip velocity conditions and by taking the side walls as insulated and the Hartmann walls as perfectly conducting. Both the domain boundary element method (DBEM) and the dual reciprocity boundary element method (DRBEM) are used in spatial discretization with a backward finite difference scheme for the time integration. These MHD equations are decoupled first into two transient convection–diffusion equations, and then into two modified Helmholtz equations by using suitable transformations. Then, the DBEM or DRBEM is used to transform these equations into equivalent integral equations by employing the fundamental solution of either steady-state convection–diffusion or modified Helmholtz equations. The DBEM and DRBEM results are presented and compared by equi-velocity and current lines at steady-state for several values of Hartmann number and the boundary perturbation parameter. 相似文献
8.
Vida Janbazi Mahnaz Hashemi 《International Journal of Adaptive Control and Signal Processing》2021,35(2):285-309
This article presents an adaptive neural compensation scheme for a class of large-scale time delay nonlinear systems in the presence of unknown dead zone, external disturbances, and actuator faults. In this article, the quadratic Lyapunov–Krasovskii functionals are introduced to tackle the system delays. The unknown functions of the system are estimated by using radial basis function neural networks. Furthermore, a disturbance observer is developed to approximate the external disturbances. The proposed adaptive neural compensation control method is constructed by utilizing a backstepping technique. The boundedness of all the closed-loop signals is guaranteed via Lyapunov analysis and the tracking errors are proved to converge to a small neighborhood of the origin. Simulation results are provided to illustrate the effectiveness of the proposed control approach. 相似文献
9.
Israel I. Zetina-Rios Gloria-L. Osorio-Gordillo Rodolfo A. Vargas-Méndez Guadalupe Madrigal-Espinosa Carlos-M. Astorga-Zaragoza 《International Journal of Adaptive Control and Signal Processing》2021,35(5):828-845
This article presents a generalized learning observer (GLO) design for the simultaneous estimation of states and actuator faults for polytopic quasi-linear parameter varying systems. The proposed approach is based on the use of a GLO, which generalized the existing results on the proportional-integral observers. Conditions of existence and stability of the observer are given through the stability analysis in the sense of Lyapunov. Its design is obtained in terms of a set of linear matrix inequalities. The performance of the proposed method is evaluated by simulation in a one-link-flexible joint robot system. 相似文献
10.
S. Aranovskiy R. Ortega J. G. Romero D. Sokolov 《International journal of control》2019,92(7):1620-1633
It is shown in the paper that the problem of speed observation for mechanical systems that are partially linearisable via coordinate changes admits a very simple and robust (exponentially stable) solution with a Luenberger-like observer. This result should be contrasted with the very complicated observers based on immersion and invariance reported in the literature. A second contribution of the paper is to compare, via realistic simulations and highly detailed experiments, the performance of the proposed observer with well-known high-gain and sliding mode observers. In particular, to show that – due to their high sensitivity to noise, that is unavoidable in mechanical systems applications – the performance of the two latter designs is well below par. 相似文献