全文获取类型
收费全文 | 936篇 |
免费 | 11篇 |
国内免费 | 43篇 |
专业分类
化学 | 20篇 |
力学 | 28篇 |
综合类 | 1篇 |
数学 | 872篇 |
物理学 | 69篇 |
出版年
2023年 | 10篇 |
2022年 | 18篇 |
2021年 | 18篇 |
2020年 | 17篇 |
2019年 | 24篇 |
2018年 | 19篇 |
2017年 | 16篇 |
2016年 | 14篇 |
2015年 | 13篇 |
2014年 | 35篇 |
2013年 | 140篇 |
2012年 | 28篇 |
2011年 | 51篇 |
2010年 | 44篇 |
2009年 | 89篇 |
2008年 | 72篇 |
2007年 | 61篇 |
2006年 | 49篇 |
2005年 | 25篇 |
2004年 | 27篇 |
2003年 | 24篇 |
2002年 | 16篇 |
2001年 | 13篇 |
2000年 | 13篇 |
1999年 | 19篇 |
1998年 | 21篇 |
1997年 | 23篇 |
1996年 | 19篇 |
1995年 | 17篇 |
1994年 | 9篇 |
1993年 | 8篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1990年 | 6篇 |
1989年 | 2篇 |
1987年 | 2篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1974年 | 2篇 |
排序方式: 共有990条查询结果,搜索用时 62 毫秒
101.
102.
Representation of a given nonnegative multivariate polynomial in terms of a sum of squares of polynomials has become an essential subject in recent developments of sums of squares optimization and semidefinite programming (SDP) relaxation of polynomial optimization problems. We discuss effective methods to obtain a simpler representation of a sparse polynomial as a sum of squares of sparse polynomials by eliminating redundancy.A considerable part of this work was conducted while this author was visiting Tokyo Institute of Technology. Research supported by Kosef R004-000-2001-00200Mathematics Subject Classification (1991): 90C22, 90C26, 90C30 相似文献
103.
Vladimir Andrievskii 《Journal of Approximation Theory》2005,133(2):1191-244
The Dzjadyk-type theorem concerning the polynomial approximation of functions on a continuum in the complex plane is generalized to the case of polynomial approximation of functions on a compact set in which consists of a finite number of continua. 相似文献
104.
105.
106.
H.L. Krall and I.M. Sheffer considered the problem of classifying certain second-order partial differential equations having an algebraically complete, weak orthogonal bivariate polynomial system of solutions. Two of the equations that they considered are
(x2+y)uxx+2xyuxy+y2uyy+gxux+g(y−1)uy=λu, 相似文献
107.
Quantitative predictions of the behavior of many deterministic systems are uncertain due to ubiquitous heterogeneity and insufficient characterization by data. We present a computational approach to quantify predictive uncertainty in complex phenomena, which is modeled by (partial) differential equations with uncertain parameters exhibiting multi-scale variability. The approach is motivated by flow in random composites whose internal architecture (spatial arrangement of constitutive materials) and spatial variability of properties of each material are both uncertain. The proposed two-scale framework combines a random domain decomposition (RDD) and a probabilistic collocation method (PCM) on sparse grids to quantify these two sources of uncertainty, respectively. The use of sparse grid points significantly reduces the overall computational cost, especially for random processes with small correlation lengths. A series of one-, two-, and three-dimensional computational examples demonstrate that the combined RDD–PCM approach yields efficient, robust and non-intrusive approximations for the statistics of diffusion in random composites. 相似文献
108.
We analyze the superconvergence property of the linear finite element method based on the polynomial preserving recovery(PPR)for Robin boundary elliptic problems on triangulartions.First,we improve the convergence rate between the finite element solution and the linear interpolation under the H1-norm by introducing a class of meshes satisfying the Condition(α,σ,μ).Then we prove the superconvergence of the recovered gradients post-processed by PPR and define an asymptotically exact a posteriori error estimator.Finally,numerical tests are provided to verify the theoretical findings. 相似文献
109.
本文从最小多项式出发,通过寻找包含奇异线性系统Ax=b最小范数解的一个解空间,获得了一个更简单的求解广义逆的计算公式.并从理论上对最小二乘QR分解算法(LSQR)收敛性进行了简单分析,分析表明LSQR的收敛性与矩阵A的非零奇异值密切相关,并用A的非零奇异值以及所寻找到的最小范数解空间将最小范数解线性表出. 相似文献
110.
《Mathematische Nachrichten》2018,291(1):7-23
We compute Betti numbers of both the components of the moduli space of rank 2 semi‐stable torsion‐free sheaves with fixed determinant over a reducible nodal curve with two smooth components intersecting at a node. We also compute the intersection Betti numbers of the moduli space. 相似文献