全文获取类型
收费全文 | 26299篇 |
免费 | 2656篇 |
国内免费 | 2566篇 |
专业分类
化学 | 2340篇 |
晶体学 | 30篇 |
力学 | 2014篇 |
综合类 | 664篇 |
数学 | 20390篇 |
物理学 | 6083篇 |
出版年
2024年 | 27篇 |
2023年 | 212篇 |
2022年 | 355篇 |
2021年 | 441篇 |
2020年 | 541篇 |
2019年 | 578篇 |
2018年 | 596篇 |
2017年 | 753篇 |
2016年 | 823篇 |
2015年 | 603篇 |
2014年 | 1257篇 |
2013年 | 1772篇 |
2012年 | 1342篇 |
2011年 | 1572篇 |
2010年 | 1388篇 |
2009年 | 1773篇 |
2008年 | 1728篇 |
2007年 | 1833篇 |
2006年 | 1626篇 |
2005年 | 1527篇 |
2004年 | 1261篇 |
2003年 | 1164篇 |
2002年 | 1046篇 |
2001年 | 974篇 |
2000年 | 911篇 |
1999年 | 786篇 |
1998年 | 714篇 |
1997年 | 662篇 |
1996年 | 489篇 |
1995年 | 398篇 |
1994年 | 328篇 |
1993年 | 254篇 |
1992年 | 206篇 |
1991年 | 176篇 |
1990年 | 187篇 |
1989年 | 118篇 |
1988年 | 107篇 |
1987年 | 100篇 |
1986年 | 92篇 |
1985年 | 110篇 |
1984年 | 97篇 |
1983年 | 65篇 |
1982年 | 99篇 |
1981年 | 89篇 |
1980年 | 55篇 |
1979年 | 55篇 |
1978年 | 54篇 |
1977年 | 45篇 |
1976年 | 40篇 |
1973年 | 23篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
Typical behaviour of the solution of a linear system of equations obtained iteratively by Krylov methods can be characterized by three stages. Initially the residual diminishes steadily; this is followed by stagnation and finally rapid convergence near the algebraic grade. This study examines this behaviour in terms of the concepts of approximately invariant subspace and what we have called the analytic grade of a Krylov sequence. It is shown how the small Ritz values play a vital role in the convergence and how this knowledge helps in the construction of an effective preconditioner. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
102.
R. Norvaisa 《Lithuanian Mathematical Journal》2005,45(4):447-457
We give a characterization of Gaussian chaos laws on Banach function spaces which do not contain ℓ
∞
n
's uniformly. The result is applied to describe the convergence in law of U-processes with sample paths in certain Banach function spaces.
__________
Published in Lietuvos Matematikos Rinkinys, Vol. 45, No. 4, pp. 553–566, October–December, 2005. 相似文献
103.
Mean value in invexity analysis 总被引:1,自引:0,他引:1
In this paper, a generalization of the mean value theorem is considered in the case of functions defined on an invex set with respect to η (which is not necessarily connected). 相似文献
104.
We consider a splitting finite-difference scheme for an initial-boundary value problem for a two-dimensional nonlinear evolutionary
equation. The problem is split into nonlinear and linear parts. The linear part is also split into locally one-dimensional
equations. We prove the convergence and stability of the scheme in L
2 and C norms.
Printed in Lietuvos Matematikos Rinkinys, Vol. 45, No. 3, pp. 413–434, July–September, 2005. 相似文献
105.
B. Amaziane M. Goncharenko L. Pankratov 《Mathematical Methods in the Applied Sciences》2005,28(15):1847-1865
We study the asymptotic behaviour of the solution of a stationary quasilinear elliptic problem posed in a domain Ω(ε) of asymptotically degenerating measure, i.e. meas Ω(ε) → 0 as ε → 0, where ε is the parameter that characterizes the scale of the microstructure. We obtain the convergence of the solution and the homogenized model of the problem is constructed using the notion of convergence in domains of degenerating measure. Proofs are given using the method of local characteristics of the medium Ω(ε) associated with our problem in a variational form. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
106.
具有避难所的非自治竞争系统的持续生存和全局稳定性 总被引:2,自引:0,他引:2
考虑一个四缀块模型,其中一缀块里有三个竞争种群,另外三个分别是它们的避难所,并且种群能在竞争缀块和各自的避难所间相互扩散.在一定的条件下,我们给出了此模型的持续生存,周期性和全局稳定性. 相似文献
107.
该文利用算子半群的方法给出了取值于具有左不变度量的完备可分群的齐次Levy过程是复合Poisson过程的弱极限这一结论. 相似文献
108.
Considerthediferenceequationwithavariabledelayxn-xn-1=F(xn,xr(n),n=n0,n0+1,…(1)where(H1):F∈C(R×R,R),F(u,v)isdecreasingwithres... 相似文献
109.
Two Convergence Problems for Monotone Sequences 总被引:1,自引:0,他引:1
Eight measures of rate of convergence of monotone sequences of real numbers have been proposed and discussed in a paper by Beyer, Ebanks, and Qualls (Acta Appl. Math. 20 (1990), 267–284). These rates arose in discussions of dynamical systems. In the comparisons of these rates, two problems remained. A complete answer is given to one of the problems and a partial answer is given to the other problem. 相似文献
110.
Gunther Jäger 《Fuzzy Sets and Systems》1997,90(3):737-348
Lowen and Lowen [Applications of category theory to fuzzy subsets (Kluwer, 1992) p. 153] and Lowen et al. [Fuzzy Sets and Systems 40 (1991) 347] recently introduced the category FCS of fuzzy convergence spaces, a topological quasitopos which is a supercategory of FTS, the category of fuzzy topological spaces. In this paper, compactness in FCS is examined. Doing so we found that to define compactness as an absolute property we had to generalize the definition of fuzzy convergence space to fuzzy subsets. All basic theorems are proved including the Tychonoff product theorem. Based on the theory developed here, in a following publication, a Richardson compactification for fuzzy convergence spaces will be given. 相似文献