全文获取类型
收费全文 | 993篇 |
免费 | 90篇 |
国内免费 | 47篇 |
专业分类
化学 | 189篇 |
力学 | 50篇 |
综合类 | 6篇 |
数学 | 599篇 |
物理学 | 286篇 |
出版年
2024年 | 6篇 |
2023年 | 42篇 |
2022年 | 12篇 |
2021年 | 16篇 |
2020年 | 15篇 |
2019年 | 44篇 |
2018年 | 25篇 |
2017年 | 25篇 |
2016年 | 40篇 |
2015年 | 23篇 |
2014年 | 49篇 |
2013年 | 107篇 |
2012年 | 70篇 |
2011年 | 64篇 |
2010年 | 59篇 |
2009年 | 83篇 |
2008年 | 66篇 |
2007年 | 56篇 |
2006年 | 41篇 |
2005年 | 25篇 |
2004年 | 29篇 |
2003年 | 18篇 |
2002年 | 20篇 |
2001年 | 19篇 |
2000年 | 7篇 |
1999年 | 15篇 |
1998年 | 6篇 |
1997年 | 8篇 |
1996年 | 12篇 |
1995年 | 19篇 |
1994年 | 10篇 |
1993年 | 5篇 |
1991年 | 7篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1985年 | 8篇 |
1984年 | 3篇 |
1983年 | 7篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 11篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 8篇 |
排序方式: 共有1130条查询结果,搜索用时 203 毫秒
141.
Quasi-projective synchronization analysis for delayed stochastic quaternion-valued neural networks via state-feedback control strategy
下载免费PDF全文
![点击此处可从《Journal of Applied Analysis & Computation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
In this paper, we explore the complete synchronization and quasi-projective synchronization in a class of stochastic delayed quaternion-valued neural networks, utilizing a state-feedback control scheme. The studied neural networks into real-valued networks are short of known decomposing, by designing a very general nonlinear controller, according to the quaternion form It\^{o} formula with a number of inequality techniques in the configuration of quaternion domain, we obtained a quasi-projective synchronization criterion for drive-response networks. Moreover, we estimate the error margin for quasi-projective synchronization. At last, the theoretical results are confirmed by a numerical simulation. 相似文献
142.
Exponential stability and applications of switched positive linear impulsive systems with time-varying delays and all unstable subsystems
下载免费PDF全文
![点击此处可从《Journal of Applied Analysis & Computation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The global uniform exponential stability of switched positive linear impulsive systems with time-varying delays and all unstable subsystems
is studied in this paper, which includes two types of distributed time-varying delays and discrete time-varying delays. Switching behaviors dominating the switched systems can be either stabilizing and destabilizing in the new designed switching sequence. We design new linear programming algorithm process to find the feasible ratio of stabilizing switching behaviors, which can be compensated by unstable subsystems, destabilizing switching behaviors, and impulses. Specically, we add a kind of nonnegative impulses which is consistent with the switching behaviors for the systems. Employing a multiple co-positive Lyapunov-Krasovskii functional, we present several new sufficient stability criteria and design new switching sequence. Then, we apply the obtained stability criteria to the exponential consensus of linear delayed multi-agent systems, and obtain the new exponential consensus criteria. Three simulations are provided to demonstrate the proposed stability criteria. 相似文献
143.
In this paper, a general non-autonomous n-species Lotka-Volterra model with delays and stochastic perturbation is investigated. For this model, sufficient conditions for extinction, non-persistence in the mean, weak persistence and stochastic permanence are established. The influences of the stochastic noises to the properties of the stochastic model are discussed. The property permanence for the model is preserved with the sufficiently small noise and sufficiently large noise may cause extinction of the model. The critical value between weak persistence and extinction is obtained. Finally, numerical simulations are given to support the theoretical analysis results. 相似文献
144.
A new technique for the latent state estimation of a wide class of nonlinear time series models is proposed. In particular, we develop a partially linearized sigma point filter in which random samples of possible state values are generated at the prediction step using an exact moment-matching algorithm and then a linear programming based procedure is used in the update step of the state estimation. The effectiveness of the new filtering procedure is assessed via a simulation example that deals with a highly nonlinear, multivariate time series representing an interest rate process. 相似文献
145.
一类具有垂直传染与脉冲免疫的SEIR传染病模型的全局分析 总被引:2,自引:0,他引:2
考虑了一个具有垂直传染与积分时滞的SEIR传染病动力学模型.分析了该模型在脉冲免疫接种条件下的动力学行为,获得了传染病灭绝的充分条件,进而运用脉冲时滞泛函微分方程理论,获得了含有时滞的系统持久性的充分条件,并且证明了积分时滞与脉冲免疫能对模型的动力学行为产生显著的影响. 相似文献
146.
利用重合度理论中的延拓定理和微分不等式技巧,给出了具有状态依赖时滞和分布时滞的脉冲细胞神经网络的周期解的存在性的充分条件. 相似文献
147.
认识高等数学阅读能力的重要性、激发大学生对高数学阅读的兴趣、提供数学阅读的具体方法是培养高等数学阅读能力的措施.其中,数学阅读的具体方法有:带有问题阅读、督促学生作读书笔记、个别指导、组织课堂讨论和经验交流、及时小结、合理评价等.高等数学教师应该努力探寻提高大学生数学阅读能力的有效方法. 相似文献
148.
149.
In this paper, the asymptotic stability for singular differential nonlinear systems with multiple time-varying delays is considered. The V-functional method for general singular differential delay system is investigated. The asymptotic stability criteria for singular differential nonlinear systems with multiple time-varying delays are derived based on V-functional method and some analytical techniques, which are described as matrix equations or matrix inequalities. The results obtained are computationally flexible and efficient. 相似文献
150.
In this paper, we propose and investigate a new general model of fuzzy stochastic discrete-time complex networks (SDCNs) described by Takagi–Sugeno (T–S) fuzzy model with discrete and distributed time-varying delays. The proposed model takes some well-studied models as special cases. By employing a new Lyapunov functional candidate, we utilize some stochastic analysis techniques and Kronecker product to deduce delay-dependent synchronization criteria that ensure the mean-square synchronization of the proposed T–S fuzzy SDCNs with mixed time-varying delays. These sufficient conditions are computationally efficient as it can be solved numerically by the LMI toolbox in Matlab. A numerical simulation example is provided to verify the effectiveness and the applicability of the proposed approach. 相似文献