全文获取类型
收费全文 | 279篇 |
免费 | 7篇 |
国内免费 | 19篇 |
专业分类
化学 | 111篇 |
晶体学 | 1篇 |
力学 | 26篇 |
数学 | 121篇 |
物理学 | 25篇 |
无线电 | 21篇 |
出版年
2024年 | 1篇 |
2023年 | 8篇 |
2022年 | 5篇 |
2021年 | 17篇 |
2020年 | 5篇 |
2019年 | 4篇 |
2018年 | 4篇 |
2016年 | 4篇 |
2015年 | 5篇 |
2014年 | 22篇 |
2013年 | 16篇 |
2012年 | 16篇 |
2011年 | 19篇 |
2010年 | 18篇 |
2009年 | 22篇 |
2008年 | 20篇 |
2007年 | 18篇 |
2006年 | 20篇 |
2005年 | 10篇 |
2004年 | 9篇 |
2003年 | 6篇 |
2002年 | 5篇 |
2001年 | 9篇 |
2000年 | 3篇 |
1999年 | 8篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 7篇 |
1994年 | 1篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 3篇 |
排序方式: 共有305条查询结果,搜索用时 0 毫秒
101.
Junfeng Zhang Zhengzhi Han Jun Huang 《Communications in Nonlinear Science & Numerical Simulation》2013,18(10):2790-2800
This paper is concerned with the stabilization of differential inclusions. By using control Lyapunov functions, a design method of homogeneous controllers for differential equation systems is first addressed. Then, the design method is developed to two classes of differential inclusions without uncertainties: homogeneous differential inclusions and nonhomogeneous ones. By means of homogeneous domination theory, a homogeneous controller for differential inclusions with uncertainties is constructed. Comparing to the existing results in the literature, an improved formula of homogeneous controllers is proposed, and the difficulty of the controller design for uncertain differential inclusions is reduced. Finally, two simulation examples are given to verify the preset design. 相似文献
102.
Jia Li Baojun Song Xiaohong Wang 《Journal of Difference Equations and Applications》2013,19(4):309-321
Based on the classical discrete Ricker population model, we incorporate Allee effects by assuming rectangular hyperbola, or Holling-II type functional form, for the birth or growth function and formulate an extended Ricker model. We explore the dynamics features of the extended Ricker model. We obtain domains of attraction for the trivial fixed point. We determine conditions for the existence and stability of positive fixed points and find regions where there exist no positive fixed points, two positive fixed points one of which is stable and two positive fixed points both of which are unstable. We demonstrate that the model exhibits period-doubling bifurcations and investigate the existence and stability of the cycles. We also confirm that Allee effects have stabilization effects, by different measures, through numerical simulations. 相似文献
103.
Sebastian Ani?a 《Nonlinear Analysis: Real World Applications》2012,13(2):725-735
A two-component reaction-diffusion system modelling a class of spatially structured epidemic systems is considered. The system describes the spatial spread of infectious diseases mediated by environmental pollution. A relevant problem, related to the possible eradication of the epidemic, is the so called zero stabilization. In a series of papers, necessary conditions, and sufficient conditions of stabilizability have been obtained. It has been proved that it is possible to diminish exponentially the epidemic process in the whole habitat, just by reducing the concentration of the pollutant in a nonempty and sufficiently large subset of the spatial domain. The stabilizability with a feedback control of the harvesting type is related to the magnitude of the principal eigenvalue of a certain operator which is not selfadjoint. In this paper, we have proposed an approximating method for this principal eigenvalue. Further, we have faced the problem of finding the optimal position (by translation) of the support of the feedback stabilizing control in order to minimize both the infected population and the pollutant at a certain finite time. 相似文献
104.
One of the major application fields for solid dielectric polymers is their use as insulating materials for power cables. Since the electrical aging of the insulating polymeric materials is one of the most important factors affecting the service lifetime of power cables, developing a model which can be used to design materials with an improved resistance to electrical degradation would be highly beneficial. We developed a model for the electrical field within the polymer material contaminated with a sharp conducting defect (a metallic needle) and defined a parameter characterizing the resistance of polymer to electrical treeing. The model was used to analyse data for the electrical degradation of polyethylene stabilized with polycyclic aromatic hydrocarbons. Based on quantum mechanically calculated electron affinities and ionisation potentials of the stabilizer molecules, we discovered that if a molecule is to be considered for voltage stabilization use it has to have a specific combination of the ionisation potential and adiabatic electron affinity. The model allows for a choice of appropriate voltage stabilizers based on theoretical calculations only and can help to facilitate any experimental study for choosing appropriate voltage stabilizer additives. 相似文献
105.
N. Levan 《Journal of Optimization Theory and Applications》1985,45(3):397-406
This paper studies strong stability of the class of strongly continuous Hilbert space semigroups which are quasi-affine transforms of contraction semigroups. Sufficient conditions for such a semigroup to be approximately strong stable are given. Applications to the stabilizability problem of Hilbert space semigroups, using a feedback involving a solution of the steady-state Riccati equation, are made. Our key tool is the generalization of the LaSalle invariance principle by Hale.This research was supported by the United States Air Force Office of Scientific Research, Directorate of Mathematical and Information Sciences, under Grant No. AFOSR-79-0053D. 相似文献
106.
A feedback stabilization problem for switched linear systems with time-delay in detection of switching signal is formulated. First, online state feedback controller design method for asymptotic stability and exponential stability is given. Then, offline state feedback controller design method for asymptotic stability and exponential stability is given as well. 相似文献
107.
Tomás Caraballo Peter E. Kloeden Björn Schmalfuß 《Applied Mathematics and Optimization》2004,50(3):183-207
We consider the exponential stability of stochastic evolution
equations with Lipschitz continuous non-linearities when zero is
not a solution for these equations. We prove the existence of a
non-trivial stationary solution which is exponentially stable,
where the stationary solution is generated by the composition of a
random variable and the Wiener shift. We also construct stationary
solutions with the stronger property of attracting bounded sets
uniformly. The existence of these stationary solutions follows
from the theory of random dynamical systems and their attractors.
In addition, we prove some perturbation results and formulate
conditions for the existence of stationary solutions for
semilinear stochastic partial differential equations with
Lipschitz continuous non-linearities. 相似文献
108.
该文证明了受内反馈控制的phase-field系统的解在某些条件下是稳定的. 相似文献
109.
110.
Emmanuel Moulay Romain Bourdais Wilfrid Perruquetti 《Nonlinear Analysis: Hybrid Systems》2007,1(4):482-490
In this paper, we study the stabilization of general nonlinear switched systems by using control Lyapunov functions. The concept of control Lyapunov function for nonlinear control systems is generalized to switched control systems. The first part of our contribution provides a necessary and sufficient condition of stabilization. The main idea is to use a common control Lyapunov function; this is achieved with the converse Lyapunov theorem dedicated to switched systems. In the second part, an explicit construction of a common control Lyapunov function is addressed with respect to a finite family of switched systems. The approach uses a family of control Lyapunov functions attached to the subsystems. 相似文献