全文获取类型
收费全文 | 4842篇 |
免费 | 310篇 |
国内免费 | 32篇 |
专业分类
化学 | 3341篇 |
晶体学 | 57篇 |
力学 | 175篇 |
数学 | 766篇 |
物理学 | 845篇 |
出版年
2023年 | 29篇 |
2022年 | 101篇 |
2021年 | 149篇 |
2020年 | 101篇 |
2019年 | 197篇 |
2018年 | 155篇 |
2017年 | 111篇 |
2016年 | 245篇 |
2015年 | 155篇 |
2014年 | 248篇 |
2013年 | 487篇 |
2012年 | 283篇 |
2011年 | 293篇 |
2010年 | 209篇 |
2009年 | 203篇 |
2008年 | 218篇 |
2007年 | 207篇 |
2006年 | 204篇 |
2005年 | 171篇 |
2004年 | 158篇 |
2003年 | 133篇 |
2002年 | 177篇 |
2001年 | 74篇 |
2000年 | 109篇 |
1999年 | 64篇 |
1998年 | 41篇 |
1997年 | 47篇 |
1996年 | 35篇 |
1995年 | 36篇 |
1994年 | 35篇 |
1993年 | 37篇 |
1992年 | 33篇 |
1991年 | 23篇 |
1990年 | 17篇 |
1989年 | 29篇 |
1988年 | 28篇 |
1987年 | 21篇 |
1986年 | 18篇 |
1985年 | 30篇 |
1984年 | 27篇 |
1983年 | 23篇 |
1982年 | 21篇 |
1981年 | 26篇 |
1980年 | 16篇 |
1979年 | 15篇 |
1978年 | 15篇 |
1977年 | 9篇 |
1976年 | 13篇 |
1975年 | 17篇 |
1959年 | 8篇 |
排序方式: 共有5184条查询结果,搜索用时 656 毫秒
21.
22.
Convergent Algorithm Based on Progressive Regularization for Solving Pseudomonotone Variational Inequalities 总被引:2,自引:2,他引:0
In this paper, we extend the Moreau-Yosida regularization of monotone variational inequalities to the case of weakly monotone and pseudomonotone operators. With these properties, the regularized operator satisfies the pseudo-Dunn property with respect to any solution of the variational inequality problem. As a consequence, the regularized version of the auxiliary problem algorithm converges. In this case, when the operator involved in the variational inequality problem is Lipschitz continuous (a property stronger than weak monotonicity) and pseudomonotone, we prove the convergence of the progressive regularization introduced in Refs. 1, 2. 相似文献
23.
Abed Al-Aziz Al-Quntar 《Journal of organometallic chemistry》2005,690(10):2504-2514
This article describes our recent methods for the synthesis of substituted vinylphosphonates by reacting 1-alkynylphosphnates with group (IV) complexes. cis-Vinylphosphonates, 1,3-butadienylphosphonates, 1-(hydroxymethyl)vinylphosphonates, 2-(hydroxymethyl)vinylphosphonates, (E) 3-oxo-1-alkenylphosphonates were produced as a result of the reactions between zirconium complexes and 1-alkynylphosphonates. On the other hand, titanium complexes afford 3-aminovinylphoshonates, 1,4-bis-phosphonates, and various other di- and tri-substituted vinylphosphonates. An evaluation of access of these recently synthesized vinylphosphonates as MMP-2 inhibitors has shown that certain compounds are very potent and promising. 相似文献
24.
El Kebir Boukas Peng Shi Sing Kiong Nguang 《Journal of Mathematical Analysis and Applications》2003,282(1):241-255
This paper studies the problem of stochastic stability and disturbance attenuation for a class of linear continuous-time uncertain systems with Markovian jumping parameters. The uncertainties are assumed to be nonlinear and state, control and external disturbance dependent. A sufficient condition is provided to solve the above problem. An H∞ controller is designed such that the resulting closed-loop system is stochastically stable and has a disturbance attenuation γ for all admissible uncertainties. It is shown that the control law is in terms of the solutions of a set of coupled Riccati inequalities. A numerical example is included to demonstrate the potential of the proposed technique. 相似文献
25.
A 27Al nuclear magnetic resonance (NMR) investigation at room temperature of the Pb1 − xAlxF2 + x (0 ≤ x ≤ 0.12) solid solution and of the ordered Pb9Al2F24 phase is carried out. Two different types of aluminium ions are identified and their ratio is determined as a function of x. A clustering process based on the formation of column clusters, more and more extended when x increases, is proposed on the basis of results issued from the 19F (Part I) and 27Al NMR investigations. 相似文献
26.
27.
Elói Medina Galego 《Monatshefte für Mathematik》2002,136(2):87-97
We study the relation of to the subspaces and quotients of Banach spaces of continuous vector-valued functions , where K is an arbitrary dispersed compact set. More precisely, we prove that every infinite dimensional closed subspace of totally incomparable to X contains a copy of complemented in . This is a natural continuation of results of Cembranos-Freniche and Lotz-Peck-Porta. We also improve our result when K is homeomorphic to an interval of ordinals. Next we show that complemented subspaces (resp., quotients) of which contain no copy of are isomorphic to complemented subspaces (resp., quotients) of some finite sum of X. As a consequence, we prove that every infinite dimensional quotient of which is quotient incomparable to X, contains a complemented copy of . Finally we present some more geometric properties of spaces.
Received 8 November 2000; in revised form 7 December 2001 相似文献
28.
E.H. El Abdalaoui F. Parreau A.A. Prikhod'ko 《Annales de l'Institut Henri Poincaré (B) Probabilités et Statistiques》2006,42(6):671-681
It is shown that for any family of probability measures in Ornstein type constructions, the corresponding transformation has almost surely a singular spectrum. This is a new generalization of Bourgain's theorem [J. Bourgain, On the spectral type of Ornstein class one transformations, Israel J. Math. 84 (1993) 53–63], same result is proved for Rudolph's construction [D. Rudolph, An example of a measure-preserving map with minimal self-joining and applications, J. Anal. Math. 35 (1979) 97–122]. 相似文献
29.
M. N. El Tarazi 《BIT Numerical Mathematics》1990,30(3):484-489
The interpolation problem at uniform mesh points of a quadratic splines(x
i)=f
i,i=0, 1,...,N ands(x
0)=f0 is considered. It is known that s–f=O(h
3) and s–f=O(h
2), whereh is the step size, and that these orders cannot be improved. Contrary to recently published results we prove that superconvergence cannot occur for any particular point independent off other than mesh points wheres=f by assumption. Best error bounds for some compound formulae approximatingf
i
andf
i
(3)
are also derived. 相似文献
30.