全文获取类型
收费全文 | 8745篇 |
免费 | 1190篇 |
国内免费 | 850篇 |
专业分类
化学 | 2326篇 |
晶体学 | 114篇 |
力学 | 1307篇 |
综合类 | 191篇 |
数学 | 3348篇 |
物理学 | 3499篇 |
出版年
2024年 | 15篇 |
2023年 | 86篇 |
2022年 | 196篇 |
2021年 | 245篇 |
2020年 | 264篇 |
2019年 | 222篇 |
2018年 | 233篇 |
2017年 | 323篇 |
2016年 | 353篇 |
2015年 | 290篇 |
2014年 | 462篇 |
2013年 | 725篇 |
2012年 | 452篇 |
2011年 | 530篇 |
2010年 | 461篇 |
2009年 | 564篇 |
2008年 | 589篇 |
2007年 | 547篇 |
2006年 | 538篇 |
2005年 | 464篇 |
2004年 | 381篇 |
2003年 | 377篇 |
2002年 | 306篇 |
2001年 | 284篇 |
2000年 | 260篇 |
1999年 | 220篇 |
1998年 | 191篇 |
1997年 | 178篇 |
1996年 | 169篇 |
1995年 | 158篇 |
1994年 | 95篇 |
1993年 | 87篇 |
1992年 | 73篇 |
1991年 | 56篇 |
1990年 | 55篇 |
1989年 | 60篇 |
1988年 | 50篇 |
1987年 | 29篇 |
1986年 | 22篇 |
1985年 | 38篇 |
1984年 | 36篇 |
1983年 | 9篇 |
1982年 | 24篇 |
1981年 | 17篇 |
1980年 | 4篇 |
1979年 | 15篇 |
1977年 | 6篇 |
1975年 | 4篇 |
1973年 | 6篇 |
1957年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
991.
Asymptotic properties of fractional delay differential equations 总被引:1,自引:0,他引:1
Katja Krol 《Applied mathematics and computation》2011,218(5):1515-1532
In this paper we study the asymptotic properties of d-dimensional linear fractional differential equations with time delay. We present necessary and sufficient conditions for asymptotic stability of equations of this type using the inverse Laplace transform method and prove polynomial decay of stable solutions. Two examples illustrate the obtained analytical results. 相似文献
992.
Franciszek Grabski 《Applied mathematics and computation》2011,217(24):9956-9965
Usually, a reliability function is defined by a failure rate which is a real function taking the non-negative real values. In this paper the failure rate is assumed to be a stochastic process with non-negative and right continuous trajectories. The reliability function is defined as an expectation of a function of that random process. Particularly, the failure rate defined by the semi-Markov processes is considered here. The theorems dealing with the renewal equations for the conditional reliability functions with a semi-Markov process as a failure rate are presented in this paper. A system of that kind of equations for the discrete state space semi-Markov process is applied for calculating the reliability function for the 3-states semi-Markov random walk. Using the introduced system of renewal equations for the countable state space, the reliability function for the Furry-Yule failure rate process is obtained. 相似文献
993.
Eric C.K. Cheung 《Insurance: Mathematics and Economics》2011,48(3):384-397
In a general Sparre Andersen risk model with surplus-dependent premium income, the generalization of Gerber-Shiu function proposed by Cheung et al. (2010a) is studied. A general expression for such Gerber-Shiu function is derived, and it is shown that its determination reduces to the evaluation of a transition function which is independent of the penalty function. Properties of and explicit expressions for such a transition function are derived when the surplus process is subject to (i) constant premium; (ii) a threshold dividend strategy; or (iii) credit interest. Extension of the approach is discussed for an absolute ruin model with debit interest. 相似文献
994.
Yong-jiang Guo 《应用数学学报(英文版)》2011,27(1):43-58
A GI/G/1 queue with vacations is considered in this paper.We develop an approximating technique on max function of independent and identically distributed(i.i.d.) random variables,that is max{ηi,1 ≤ i ≤ n}.The approximating technique is used to obtain the fluid approximation for the queue length,workload and busy time processes.Furthermore,under uniform topology,if the scaled arrival process and the scaled service process converge to the corresponding fluid processes with an exponential rate,we prove by the... 相似文献
995.
We consider the long‐time behavior and optimal decay rates of global strong solution to three‐dimensional isentropic compressible Navier–Stokes (CNS) system in the present paper. When the regular initial data also belong to some Sobolev space with l?4 and s∈[0, 1], we show that the global solution to the CNS system converges to the equilibrium state at a faster decay rate in time. In particular, the density and momentum converge to the equilibrium state at the rates (1 + t)?3/4?s/2 in the L2‐norm or (1 + t)?3/2?s/2 in the L∞‐norm, respectively, which are shown to be optimal for the CNS system. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
996.
Jessica S. Kenigson Jonathan J. Kenigson 《Mathematical Methods in the Applied Sciences》2011,34(1):48-62
We study the asymptotic behavior of solutions of dissipative wave equations with space–time‐dependent potential. When the potential is only time‐dependent, Fourier analysis is a useful tool to derive sharp decay estimates for solutions. When the potential is only space‐dependent, a powerful technique has been developed by Todorova and Yordanov to capture the exact decay of solutions. The presence of a space–time‐dependent potential, as in our case, requires modifications of this technique. We find the energy decay and decay of the L2 norm of solutions in the case of space–time‐dependent potential. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
997.
本文研究了误差为鞅差序列情形下的半参数回归模型.利用小波方法,在相当一般的条件下,得到了参数、非参数估计量的弱收敛速度. 相似文献
998.
本文研究了基于相依函数型数据非参数回归函数的核估计.利用稳健的方法,在一定条件下获得了与i.i.d.场合下类似的估计量的几乎完全收敛速度,推广了现有文献中的相关结论. 相似文献
999.
Sergey G. Foss Anatolii A. Puhalskii 《Stochastic Processes and their Applications》2011,121(2):288-313
We consider a random walk with a negative drift and with a jump distribution which under Cramér’s change of measure belongs to the domain of attraction of a spectrally positive stable law. If conditioned to reach a high level and suitably scaled, this random walk converges in law to a nondecreasing Markov process which can be interpreted as a spectrally positive Lévy process conditioned not to overshoot level 1. 相似文献
1000.
A non-autonomous SIR model with periodic transmission rate and a constant removal rate is formulated. By using the continuation theorem of coincidence degree theory, sufficient conditions for the existence of at least two positive periodic solutions are obtained. The stability of the periodic solution for small seasonality is investigated. Numerical simulations are done to show our theoretical results. 相似文献