全文获取类型
收费全文 | 10925篇 |
免费 | 717篇 |
国内免费 | 926篇 |
专业分类
电工技术 | 710篇 |
综合类 | 1038篇 |
化学工业 | 813篇 |
金属工艺 | 311篇 |
机械仪表 | 753篇 |
建筑科学 | 458篇 |
矿业工程 | 173篇 |
能源动力 | 237篇 |
轻工业 | 246篇 |
水利工程 | 84篇 |
石油天然气 | 113篇 |
武器工业 | 77篇 |
无线电 | 1175篇 |
一般工业技术 | 837篇 |
冶金工业 | 224篇 |
原子能技术 | 266篇 |
自动化技术 | 5053篇 |
出版年
2024年 | 12篇 |
2023年 | 71篇 |
2022年 | 123篇 |
2021年 | 138篇 |
2020年 | 161篇 |
2019年 | 222篇 |
2018年 | 201篇 |
2017年 | 281篇 |
2016年 | 304篇 |
2015年 | 339篇 |
2014年 | 607篇 |
2013年 | 716篇 |
2012年 | 608篇 |
2011年 | 867篇 |
2010年 | 596篇 |
2009年 | 759篇 |
2008年 | 694篇 |
2007年 | 720篇 |
2006年 | 621篇 |
2005年 | 585篇 |
2004年 | 493篇 |
2003年 | 476篇 |
2002年 | 407篇 |
2001年 | 347篇 |
2000年 | 311篇 |
1999年 | 345篇 |
1998年 | 251篇 |
1997年 | 166篇 |
1996年 | 157篇 |
1995年 | 130篇 |
1994年 | 134篇 |
1993年 | 103篇 |
1992年 | 81篇 |
1991年 | 70篇 |
1990年 | 62篇 |
1989年 | 63篇 |
1988年 | 52篇 |
1987年 | 38篇 |
1986年 | 46篇 |
1985年 | 55篇 |
1984年 | 46篇 |
1983年 | 36篇 |
1982年 | 26篇 |
1981年 | 13篇 |
1980年 | 15篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1973年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
991.
Elena N. Gryazina Author Vitae Author Vitae 《Automatica》2006,42(1):13-26
The challenging problem in linear control theory is to describe the total set of parameters (controller coefficients or plant characteristics) which provide stability of a system. For the case of one complex or two real parameters and SISO system (with a characteristic polynomial depending linearly on these parameters) the problem can be solved graphically by use of the so-called D-decomposition. Our goal is to extend the technique and to link it with general M-Δ framework. In this way we investigate the geometry of D-decomposition for polynomials and estimate the number of root invariant regions. Several examples verify that these estimates are tight. We also extend D-decomposition for the matrix case, i.e. for MIMO systems. For instance, we partition real axis or complex plane of the parameter k into regions with invariant number of stable eigenvalues of the matrix A+kB. Similar technique can be applied to double-input double-output systems with two parameters. 相似文献
992.
In this paper, the stochastic stabilization problem for a class of Markov jumping linear systems (MJLS) subject to actuator saturation is considered. The concept of domain of attraction in mean square sense is used to analyze the closed-loop stability. When the jumping mode is available, a mode-dependent state feedback controller is developed. Otherwise, we give a less conservative approach to design the mode-independent state feedback controller. Both design procedures can be converted into a set of linear matrix inequalities (LMIs). Finally, a numerical example is provided to show the effectiveness of the techniques. 相似文献
993.
In this paper, we consider multi-inventory systems in the presence of uncertain demand. We assume that (i) demand is unknown but bounded in an assigned compact set and (ii) the control inputs (controlled flows) are subject to assigned constraints. Given a long-term average demand, we select a nominal flow that feeds such a demand. In this context, we are interested in a control strategy that meets at each time all possible current demands and achieves the nominal flow in the average. We provide necessary and sufficient conditions for such a strategy to exist and we characterize the set of achievable flows. Such conditions are based on linear programming and thus they are constructive. In the special case of a static flow (i.e. a system with 0-capacity buffers) we show that the strategy must be affine. The dynamic problem can be solved by a linear-saturated control strategy (inspired by the previous one). We provide numerical analysis and illustrative examples. 相似文献
994.
Although 2DLDA algorithm obtains higher recognition accuracy, a vital unresolved problem of 2DLDA is that it needs huge feature matrix for the task of face recognition. To overcome this problem, this paper presents an efficient approach for face image feature extraction, namely, (2D)2LDA method. Experimental results on ORL and Yale database show that the proposed method obtains good recognition accuracy despite having less number of coefficients. 相似文献
995.
Chih-Yang Tsai 《Information Sciences》2006,176(7):772-798
We propose a two-stage model for detecting nonlinear patterns in discriminant problems and for solving the problem. The model deploys a Linear Programming Based Discriminator (LPBD) in stage one for treating linear patterns and a Probabilistic Neural Network (PNN) in stage two for handling nonlinear patterns. The LPBD in stage one divides the decision space into a clear zone where observations are (almost) linearly separable and a gray zone where nonlinear patterns are more likely to occur. The PNN in stage two analyzes the gray zone and determines whether a significant nonlinear patterns exist in the observations. Our goal is to avoid using a nonlinear model unless the PNN strongly suggests so to maintain good interpretability and avoid overfitting. Our computational study demonstrates the effectiveness of the two-stage model in both classification accuracy and computational efficiency. 相似文献
996.
LMI conditions for robust stability analysis based on polynomially parameter-dependent Lyapunov functions 总被引:3,自引:3,他引:3
The robust stability of uncertain linear systems in polytopic domains is investigated in this paper. The main contribution is to provide a systematic procedure for generating sufficient robust stability linear matrix inequality conditions based on homogeneous polynomially parameter-dependent Lyapunov matrix functions of arbitrary degree on the uncertain parameters. The conditions exploit the positivity of the uncertain parameters, being constructed in such a way that: as the degree of the polynomial increases, the number of linear matrix inequalities and free variables increases and the test becomes less conservative; if a feasible solution exists for a certain degree, the conditions will also be verified for larger degrees. For any given degree, the feasibility of a set of linear matrix inequalities defined at the vertices of the polytope assures the robust stability. Both continuous and discrete-time uncertain systems are addressed, as illustrated by numerical examples. 相似文献
997.
Robust stability of time varying polytopic systems 总被引:2,自引:2,他引:2
This paper provides global asymptotic stability conditions for time-varying continuous-time polytopic systems, using a parameter dependent Lyapunov function. The time varying parameter uncertainty as well as its time derivative are modelled as belonging to polytopic convex sets and their dependence is made explicit to get less conservative results. A particular case, characterized by the parameter uncertainty satisfying a linear differential equation is analyzed and a simpler version of the aforementioned stability conditions is presented. The results are expressed in terms of linear matrix inequalities being thus numerically solvable with no big difficulty. The theory is illustrated by the determination of the asymptotic stability region of a Mathieu's type equation with an uncertain time varying parameter. 相似文献
998.
-like control for nonlinear stochastic systems 总被引:1,自引:0,他引:1
In this paper we develop a H∞-type theory, from the dissipation point of view, for a large class of time-continuous stochastic nonlinear systems. In particular, we introduce the notion of stochastic dissipative systems analogously to the familiar notion of dissipation associated with deterministic systems and utilize it as a basis for the development of our theory. Having discussed certain properties of stochastic dissipative systems, we consider time-varying nonlinear systems for which we establish a connection between what is called the L2-gain property and the solution to a certain Hamilton–Jacobi inequality (HJI), that may be viewed as a bounded real lemma for stochastic nonlinear systems. The time-invariant case with infinite horizon is also considered, where for this case we synthesize a worst case-based stabilizing controller. Stability in this case is taken to be in the mean-square sense. In the stationary case, the problem of robust state feedback control is considered in the case of norm-bounded uncertainties. A solution is then derived in terms of linear matrix inequalities. 相似文献
999.
Controlling an approximation model of a controllable infinite dimensional linear control system does not necessarily yield a good approximation of the control needed for the continuous model. In the present paper, under the main assumptions that the discretized semigroup is uniformly analytic, and that the control operator is mildly unbounded, we prove that the semidiscrete approximation models are uniformly controllable. Moreover, we provide a computationally efficient way to compute the approximation controls. An example of application is implemented for the one- and two-dimensional heat equation with Neumann boundary control. 相似文献
1000.
胡国华 《南方冶金学院学报》2002,23(1):69-71,78
通过将数列{(1 1/n)^n}按二项式定理展开的方法,以及用到三个著名的不等式来分别证明该数列递增且有上界。 相似文献