全文获取类型
收费全文 | 8657篇 |
免费 | 1327篇 |
国内免费 | 1283篇 |
专业分类
化学 | 6826篇 |
晶体学 | 108篇 |
力学 | 580篇 |
综合类 | 103篇 |
数学 | 901篇 |
物理学 | 2749篇 |
出版年
2024年 | 36篇 |
2023年 | 169篇 |
2022年 | 316篇 |
2021年 | 385篇 |
2020年 | 406篇 |
2019年 | 392篇 |
2018年 | 341篇 |
2017年 | 332篇 |
2016年 | 413篇 |
2015年 | 440篇 |
2014年 | 515篇 |
2013年 | 675篇 |
2012年 | 752篇 |
2011年 | 772篇 |
2010年 | 586篇 |
2009年 | 522篇 |
2008年 | 557篇 |
2007年 | 471篇 |
2006年 | 423篇 |
2005年 | 365篇 |
2004年 | 268篇 |
2003年 | 260篇 |
2002年 | 252篇 |
2001年 | 209篇 |
2000年 | 170篇 |
1999年 | 178篇 |
1998年 | 108篇 |
1997年 | 100篇 |
1996年 | 97篇 |
1995年 | 95篇 |
1994年 | 66篇 |
1993年 | 83篇 |
1992年 | 63篇 |
1991年 | 57篇 |
1990年 | 56篇 |
1989年 | 45篇 |
1988年 | 31篇 |
1987年 | 25篇 |
1986年 | 20篇 |
1985年 | 26篇 |
1984年 | 16篇 |
1983年 | 17篇 |
1982年 | 17篇 |
1976年 | 12篇 |
1975年 | 15篇 |
1974年 | 10篇 |
1973年 | 10篇 |
1972年 | 16篇 |
1971年 | 9篇 |
1970年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
A lithium(I) coordination polymer has been formed from LiClO4 and the 2,2′‐bipyrimidine (bpym) ligand in which each square pyramidal lithium(I) atom is coordinated in the basal plane by four nitrogen donor atoms derived from two bpym ligands and one water molecule at the apical position. These are connected into a layer structure via hydrogen‐bonding interactions involving the perchlorate anions. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
3.
4.
In this note, we study convergence rates in the law of large numbers for independent and identically distributed random variables under sublinear expectations. We obtain a strong L^p-convergence version and a strongly quasi sure convergence version of the law of large numbers. 相似文献
5.
Based on solving the couple mode equation numerically, the characterization of the signal power on the gate power was analyzed. And the relationship of the tolerance of the grating period and the bulk temperature on the interaction length was analyzed. 相似文献
6.
7.
Each convex planar set K has a perimeter C, a minimum width E, an area A, and a diameter D. The set of points (E,C, A1/2, D) corresponding to
all such sets is shown to occupy a cone in the non-negative orthant of R4with its vertex at the origin. Its three-dimensional cross section S in the
plane D = 1 is investigated. S lies in a rectangular parallelepiped in R3. Results of Lebesgue, Kubota, Fukasawa, Sholander, and Hemmi are used to
determine some of the boundary surfaces of S, and new results are given for the other boundary surfaces. From knowledge of S, all inequalities among
E, C ,A, and D can be found. 相似文献
8.
In this paper, based on the natural boundary reduction advanced by Feng and Yu, we couple the finite element approach with the natural boundary element method to study the weak solvability and Galerkin approximation of a class of nonlinear exterior boundary value problems. The analysis is mainly based on the variational formulation with constraints. We prove the error estimate of the finite element solution and obtain the asymptotic rate of convergence. Finally, we also give a numerical example.
相似文献9.
We study the half-space problem of the nonlinear Boltzmann equation, assigning the Dirichlet data for outgoing particles
at the boundary and a Maxwellian as the far field. We will show that the solvability of the problem changes with the Mach
number ℳ∞ of the far Maxwellian. If ℳ∞<−1, there exists a unique smooth solution connecting the Dirichlet data and the far Maxwellian for any Dirichlet data sufficiently
close to the far Maxwellian. Otherwise, such a solution exists only for the Dirichlet data satisfying certain admissible conditions.
The set of admissible Dirichlet data forms a smooth manifold of codimension 1 for the case −1<ℳ∞<0, 4 for 0<ℳ∞<1 and 5 for ℳ∞>1, respectively. We also show that the same is true for the linearized problem at the far Maxwellian, and the manifold is,
then, a hyperplane. The proof is essentially based on the macro-micro or hydrodynamics-kinetic decomposition of solutions
combined with an artificial damping term and a spatially exponential decay weight.
Received: 20 April 2002 / Accepted: 4 December 2002
Published online: 21 March 2003
Communicated by H.-T. Yau 相似文献
10.