全文获取类型
收费全文 | 112525篇 |
免费 | 8797篇 |
国内免费 | 9974篇 |
专业分类
化学 | 44472篇 |
晶体学 | 698篇 |
力学 | 10844篇 |
综合类 | 1708篇 |
数学 | 34652篇 |
物理学 | 38922篇 |
出版年
2024年 | 163篇 |
2023年 | 1034篇 |
2022年 | 2161篇 |
2021年 | 2273篇 |
2020年 | 2412篇 |
2019年 | 2622篇 |
2018年 | 2251篇 |
2017年 | 2672篇 |
2016年 | 3032篇 |
2015年 | 2583篇 |
2014年 | 3936篇 |
2013年 | 7237篇 |
2012年 | 4573篇 |
2011年 | 5185篇 |
2010年 | 4339篇 |
2009年 | 6282篇 |
2008年 | 6834篇 |
2007年 | 7396篇 |
2006年 | 6638篇 |
2005年 | 5605篇 |
2004年 | 5003篇 |
2003年 | 5165篇 |
2002年 | 5269篇 |
2001年 | 4112篇 |
2000年 | 3982篇 |
1999年 | 3499篇 |
1998年 | 3310篇 |
1997年 | 2519篇 |
1996年 | 2283篇 |
1995年 | 1995篇 |
1994年 | 1944篇 |
1993年 | 1573篇 |
1992年 | 1570篇 |
1991年 | 1178篇 |
1990年 | 1036篇 |
1989年 | 879篇 |
1988年 | 788篇 |
1987年 | 666篇 |
1986年 | 576篇 |
1985年 | 612篇 |
1984年 | 609篇 |
1983年 | 313篇 |
1982年 | 482篇 |
1981年 | 539篇 |
1980年 | 385篇 |
1979年 | 384篇 |
1978年 | 309篇 |
1977年 | 296篇 |
1976年 | 216篇 |
1973年 | 159篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
181.
平行机半在线排序问题研究(Ⅰ) 总被引:15,自引:1,他引:14
对半在线平行机排序问题的研究进展作了详细综述和进一步探讨。文章给出半在线排序问题的背景、定义、分类和求解。介绍它们定义和在不同机器环境和目标函数下半在线排序问题分类,以及第一类半在线模型的近似算法的设计及其竞争比分析。 相似文献
182.
183.
A.J.?Lpez-Moreno 《Acta Mathematica Hungarica》2005,106(4):343-354
Summary We obtain preservation inequalities for Lipschitz constants of higher order in simultaneous approximation processes by Bernstein type operators. From such inequalities we derive the preservation of the corresponding Lipschitz spaces. 相似文献
184.
姜德元 《浙江大学学报(理学版)》2003,30(5):499-502
研究了NA序列重对数律收敛速度的一般形式,把Davis和Gut的结果推广到了NA的情形,并使梁汉营等人关于对数律一个结果成为特例;作为推论,得到了关于NA序列重对数律收敛速度的充分条件. 相似文献
185.
By further generalizing the skew-symmetric triangular splitting iteration method studied by Krukier, Chikina and Belokon (Applied Numerical Mathematics, 41 (2002), pp. 89–105), in this paper, we present a new iteration scheme, called the modified skew-Hermitian triangular splitting iteration method, for solving the strongly non-Hermitian systems of linear equations with positive definite coefficient matrices. We discuss the convergence property and the optimal parameters of this new method in depth. Moreover, when it is applied to precondition the Krylov subspace methods like GMRES, the preconditioning property of the modified skew-Hermitian triangular splitting iteration is analyzed in detail. Numerical results show that, as both solver and preconditioner, the modified skew-Hermitian triangular splitting iteration method is very effective for solving large sparse positive definite systems of linear equations of strong skew-Hermitian parts. 相似文献
186.
采用溶解-反应量热法在具有恒温环境的溶解-反应热量计内,测定了[Gd(Gly)4(Im)(H2O)](ClO4)3和[Y(Gly)4(Im)(H2O)](ClO4)3两种稀土甘氨酸咪唑配合物的标准生成焓分别为(-3 461.46 ±0.22) kJ·mol-1 和(-3 926.6±0.90) kJ·mol-1. 相似文献
187.
The rational and sustainable exploitation of nature resources is one of the priority objectives of our society. In this article a method is proposed to evaluate and exploit the energetic resources contained in different forest formations. This method is based on the use of a combustion bomb calorimeter to determine the calorific values of the different samples studied. These results were complemented with chemical analysis of the samples and with environmental and geomorphological studies of the zones were samples were taken. The results obtained during the last 3 years for the residual biomass originated from the forest formations existing in Galicia ensure the reliability and usefulness of the method that can be extended to any forest formation all over the world. 相似文献
188.
We extend the matrix version of Cochran's statistical theorem to outer inverses of a matrix. As applications, we investigate the Wishartness and independence of matrix quadratic forms for Kronecker product covariance structures. 相似文献
189.
INTERSECTION OF PRIME SUBMODULES AND DIMENSION OF MODULES 总被引:1,自引:0,他引:1
A.Azizi 《数学物理学报(B辑英文版)》2005,25(3):385-394
The aim of this paper is to study the conditions by which a P-prime submodule can be expressed as a finite intersection or union of P-prime submodules. Also corresponding to dimension and rank of modules, some equivalent conditions for a ring to be a Dedekind domain are given. 相似文献
190.
Basic principles of the generalized lattice model of multicomponent condensed systems are formulated. Short-range parts of interatomic interactions are taken into account by means of the geometric constraints method. Long-range parts of the interactions are taken into account in mean field approximation. The expression for Helmholtz free energy is obtained. A system of integral equations for the equilibrium distributions of components is derived. The asymptotic properties of its solutions are investigated. Moment expansion of interatomic interactions and localization of integral terms in free energy is obtained. A Ginzburg–Landau-like functional of free energy is derived. 相似文献