全文获取类型
收费全文 | 155篇 |
免费 | 12篇 |
国内免费 | 9篇 |
专业分类
化学 | 1篇 |
力学 | 24篇 |
综合类 | 10篇 |
数学 | 116篇 |
物理学 | 25篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 5篇 |
2019年 | 6篇 |
2018年 | 4篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 7篇 |
2014年 | 2篇 |
2013年 | 16篇 |
2012年 | 6篇 |
2011年 | 3篇 |
2010年 | 3篇 |
2009年 | 6篇 |
2008年 | 3篇 |
2007年 | 6篇 |
2006年 | 13篇 |
2005年 | 10篇 |
2004年 | 4篇 |
2003年 | 7篇 |
2002年 | 14篇 |
2001年 | 8篇 |
2000年 | 6篇 |
1999年 | 5篇 |
1998年 | 9篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 7篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1976年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有176条查询结果,搜索用时 15 毫秒
41.
In this paper, lower bounds of the topological entropy for nonautonomous dynamical systems are given via the growths of topological complexity in fundamental group and in degree. 相似文献
42.
César M. Silva 《Mathematical Methods in the Applied Sciences》2014,37(13):1974-1991
We obtain conditions for eradication and permanence of infection for a nonautonomous SIQR model with time‐dependent parameters that are not assumed to be periodic. The incidence is given by functions of all compartments, and the threshold conditions are given by some numbers that play the role of the basic reproduction number. We obtain simple threshold conditions in the autonomous, asymptotically autonomous and periodic settings and show that our thresholds coincide with the ones already established. Additionally, we obtain threshold conditions for the general nonautonomous model with mass‐action, standard and quarantine‐adjusted incidence. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
43.
Rui A. C. Ferreira César M. Silva 《Journal of Difference Equations and Applications》2018,24(8):1295-1317
We obtain conditions for permanence and extinction of the infection for a nonautonomous SIQR model defined on an arbitrary time scale. The threshold conditions are given by some numbers that play the role of the basic reproduction number in this setting. As a particular case of our result, we recover several threshold conditions obtained in the literature, on discrete or continuous time, for autonomous, periodic models and general nonautonomous models and we also discuss some new situations, including an aperiodic time scale. 相似文献
44.
Edgar Pereira Jacques A.L. da Silva 《Mathematical Methods in the Applied Sciences》2013,36(3):275-289
A nonautonomous SIRVS model with time‐dependent parameters is considered. The global dynamics is investigated, and conditions for the permanence, extinction, and disease‐free equilibrium are studied. Substitute quantities that replace the basic reproduction number are presented. Numerical simulations illustrate the dynamic behavior of the proposed model. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
45.
We construct analytical periodic wave and soliton solutions to the generalized nonautonomous nonlinear Schrödinger equation with time- and space-dependent distributed coefficients in harmonic and optical lattice potentials. We utilize the similarity transformation technique to obtain these solutions. Constraints for the dispersion coefficient, the nonlinearity, and the gain (loss) coefficient are presented at the same time. Various shapes of periodic wave and soliton solutions are studied analytically and physically. Stability analysis of the solutions is discussed numerically. 相似文献
46.
47.
In this paper, we consider the permanence of asymptotically periodic mul-tispecies Lotka-Volterra competition predator-prey system. By means of the standard comparison theorem, we improve or extend the corresponding results given by Peng and Chen [1], Teng and Li [2], Zhao and Chen [3]. Also, we obtain the conditions which ensure the permanence and global attractivity of asymptotically periodic multispecies competition predator-prey system. 相似文献
48.
研究具有可变时滞的非自治中立型差分方程Δ(xn-cxn-k)+h(n,xn-ln)=0,n=0,1,2,…的振动性,得到了这类差分方程振动的必要条件、充分条件和充要条件,同时得到了这类方程的最终正解存在性判据. 相似文献
49.
In this paper, we prove the invariance of Stepanov-like pseudo-almost periodic functions under bounded linear operators. Furthermore, we obtain existence and uniqueness theorems of pseudo-almost periodic mild solutions to evolution equations u′(t)=A(t)u(t)+h(t) and on , assuming that A(t) satisfy “Acquistapace–Terreni” conditions, that the evolution family generated by A(t) has exponential dichotomy, that R(λ0,A()) is almost periodic, that B,C(t,s)t≥s are bounded linear operators, that f is Lipschitz with respect to the second argument uniformly in the first argument and that h, f, F are Stepanov-like pseudo-almost periodic for p>1 and continuous. To illustrate our abstract result, a concrete example is given. 相似文献
50.
扩散的具有时滞的非自治捕食-食饵系统的持久性和全局吸引性 总被引:1,自引:1,他引:1
讨论当系数满足一定的条件时,具有连续时滞和Ho llingII类功能性反应的非自治扩散捕食-食饵系统的持久性,并给出系统周期解全局吸引的充分条件. 相似文献