全文获取类型
收费全文 | 1017篇 |
免费 | 67篇 |
国内免费 | 150篇 |
专业分类
化学 | 36篇 |
晶体学 | 1篇 |
力学 | 24篇 |
综合类 | 38篇 |
数学 | 1062篇 |
物理学 | 73篇 |
出版年
2023年 | 17篇 |
2022年 | 6篇 |
2021年 | 9篇 |
2020年 | 23篇 |
2019年 | 28篇 |
2018年 | 28篇 |
2017年 | 32篇 |
2016年 | 29篇 |
2015年 | 14篇 |
2014年 | 24篇 |
2013年 | 75篇 |
2012年 | 42篇 |
2011年 | 34篇 |
2010年 | 42篇 |
2009年 | 52篇 |
2008年 | 66篇 |
2007年 | 63篇 |
2006年 | 62篇 |
2005年 | 81篇 |
2004年 | 53篇 |
2003年 | 67篇 |
2002年 | 61篇 |
2001年 | 52篇 |
2000年 | 59篇 |
1999年 | 36篇 |
1998年 | 34篇 |
1997年 | 36篇 |
1996年 | 24篇 |
1995年 | 16篇 |
1994年 | 13篇 |
1993年 | 10篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1989年 | 7篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1936年 | 1篇 |
排序方式: 共有1234条查询结果,搜索用时 15 毫秒
1.
From Crofton's formula for Minkowski tensors we derive stereological estimators of translation invariant surface tensors of convex bodies in the n‐dimensional Euclidean space. The estimators are based on one‐dimensional linear sections. In a design based setting we suggest three types of estimators. These are based on isotropic uniform random lines, vertical sections, and non‐isotropic random lines, respectively. Further, we derive estimators of the specific surface tensors associated with a stationary process of convex particles in the model based setting. 相似文献
2.
Let R be a Noetherian ring and M be a finitely generated R-module. Let I(M) be the first nonzero Fitting ideal of M. The main result of this paper asserts that when I(M) = Q is a regular maximal ideal of R, then M?R∕Q⊕P, for some projective R-module P of constant rank if and only if T(M)?QM. As a consequence, it is shown that if M is an Artinian R-module and I(M) = Q is a regular maximal ideal of R, then M?R∕Q. 相似文献
3.
Fausto De Mari 《代数通讯》2018,46(4):1709-1715
In this paper (generalized) soluble groups for which the set of all non-modular subgroups satisfies some weak chain condition are described. Groups satisfying weak chain conditions on non-permutable subgroups are also considered. 相似文献
4.
AbstractThe well-known Jahn-Graef-Younes algorithm, proposed by Jahn in 2006, generates all minimal elements of a finite set with respect to an ordering cone. It consists of two Graef-Younes procedures, namely the forward iteration, which eliminates a part of the non-minimal elements, followed by the backward iteration, which is applied to the reduced set generated by the previous iteration. Without using the backward iteration, we develop new algorithms that also compute all minimal elements of the initial set, by combining the forward iteration with certain sorting procedures based on cone-monotone functions. In particular, when the ordering cone is polyhedral, computational results obtained in MATLAB allow us to compare our algorithms with the Jahn-Graef-Younes algorithm, within a bi-objective optimization problem. 相似文献
5.
The goal of this article is to establish estimates involving the Yamabe minimal volume, mixed minimal volume and some topological invariants on compact 4‐manifolds. In addition, we provide topological sphere theorems for compact submanifolds of spheres and Euclidean spaces, provided that the full norm of the second fundamental form is suitably bounded. 相似文献
6.
The single neutral spin-half particle with electric dipole moment and magnetic dipole moment moving in an external electromagnetic field is studied. The Aharonov-Casher effect and He-McKellar-Wilkens effect are emphatically discussed in noncommutative (NC) space with minimal length. The energy eigenvalues of the systems are obtained exactly in terms of the Jacobi polynomials. Additionally, a special case is discussed and the related energy spectra are plotted. 相似文献
7.
8.
Johannes Wittmann 《Mathematische Nachrichten》2019,292(7):1627-1635
Let M be a closed spin manifold and let N be a closed manifold. For maps and Riemannian metrics g on M and h on N, we consider the Dirac operator of the twisted Dirac bundle . To this Dirac operator one can associate an index in . If M is 2‐dimensional, one gets a lower bound for the dimension of the kernel of out of this index. We investigate the question whether this lower bound is obtained for generic tupels . 相似文献
9.
Caiyun Jin 《Numerical Functional Analysis & Optimization》2019,40(7):825-843
In this article, an approximate minimax theorem for bi-lower-semicontinuous set-valued mapping was proved, relationships between semicontinuous set-valued mappings are discussed and the existence of approximate maxmin was given. The minimax theorem in this article is the first minimax theorem that doesn’t require the set-valued mappings to be continuous. 相似文献
10.
In this paper we give sufficient conditions that guarantee the mean curvature flow with free boundary on a pinched cylinder develops a Type 2 curvature singularity. We additionally prove that Type 0 singularities may only occur at infinity. 相似文献