全文获取类型
收费全文 | 11128篇 |
免费 | 711篇 |
国内免费 | 1005篇 |
专业分类
化学 | 328篇 |
晶体学 | 2篇 |
力学 | 457篇 |
综合类 | 198篇 |
数学 | 10513篇 |
物理学 | 1346篇 |
出版年
2024年 | 14篇 |
2023年 | 114篇 |
2022年 | 156篇 |
2021年 | 164篇 |
2020年 | 239篇 |
2019年 | 254篇 |
2018年 | 249篇 |
2017年 | 302篇 |
2016年 | 282篇 |
2015年 | 229篇 |
2014年 | 460篇 |
2013年 | 857篇 |
2012年 | 444篇 |
2011年 | 561篇 |
2010年 | 508篇 |
2009年 | 651篇 |
2008年 | 774篇 |
2007年 | 780篇 |
2006年 | 683篇 |
2005年 | 642篇 |
2004年 | 505篇 |
2003年 | 526篇 |
2002年 | 422篇 |
2001年 | 393篇 |
2000年 | 351篇 |
1999年 | 334篇 |
1998年 | 309篇 |
1997年 | 283篇 |
1996年 | 202篇 |
1995年 | 129篇 |
1994年 | 113篇 |
1993年 | 98篇 |
1992年 | 92篇 |
1991年 | 84篇 |
1990年 | 61篇 |
1989年 | 47篇 |
1988年 | 55篇 |
1987年 | 41篇 |
1986年 | 38篇 |
1985年 | 57篇 |
1984年 | 47篇 |
1983年 | 25篇 |
1982年 | 42篇 |
1981年 | 41篇 |
1980年 | 38篇 |
1979年 | 36篇 |
1978年 | 38篇 |
1977年 | 22篇 |
1976年 | 23篇 |
1973年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
1.
2.
《Indagationes Mathematicae》2021,32(1):55-85
We show that the differential structure of the orbit space of a proper action of a Lie group on a smooth manifold is weakly reflexive. This implies that the orbit space is a differentiable space in the sense of Smith, which ensures that the orbit space has an exterior algebra of differential forms, that satisfies Smith’s version of de Rham’s theorem. Because the orbit space is a locally closed subcartesian space, it has vector fields and their flows. 相似文献
3.
A finite support product of clones of Jensen's minimal singleton forcing is used to define a model in which any non-empty analytically definable set of reals contains an analytically definable real (the full basis theorem), but there is no analytically definable wellordering of the reals. 相似文献
4.
5.
Liang Zhao 《Journal of Differential Equations》2019,266(9):5615-5624
In this paper, let be n-dimensional noncompact metric measure space which satisfies Poincaré inequality with some Ricci curvature condition. We obtain a Liouville theorem for positive weak solutions to weighted p-Lichnerowicz equation where are real constants. 相似文献
6.
7.
In this paper, we propose a sufficient and necessary condition for the boundedness of all the solutions for the equation with the critical situation that on g and p, where , is periodic and is bounded. 相似文献
8.
In this paper, we study the existence of the uniformly minimum risk equivariant (UMRE) estimators of parameters in a class
of normal linear models, which include the normal variance components model, the growth curve model, the extended growth curve
model, and the seemingly unrelated regression equations model, and so on. The necessary and sufficient conditions are given
for the existence of UMRE estimators of the estimable linear functions of regression coefficients, the covariance matrixV and (trV)α, where α > 0 is known, in the models under an affine group of transformations for quadratic losses and matrix losses, respectively.
Under the (extended) growth curve model and the seemingly unrelated regression equations model, the conclusions given in literature
for estimating regression coefficients can be derived by applying the general results in this paper, and the sufficient conditions
for non-existence of UMRE estimators ofV and tr(V) are expanded to be necessary and sufficient conditions. In addition, the necessary and sufficient conditions that there
exist UMRE estimators of parameters in the variance components model are obtained for the first time. 相似文献
9.
Inner derivations and norm equality 总被引:3,自引:0,他引:3
Mohamed Barraa Mohamed Boumazgour 《Proceedings of the American Mathematical Society》2002,130(2):471-476
We characterize when the norm of the sum of two bounded operators on a Hilbert space is equal to the sum of their norms.
10.
Algebra matrix and similarity classification of operators 总被引:1,自引:0,他引:1
ZHANG Zilong & LI Yucheng Department of Mathematics Hebei Normal University Shijiazhuang China 《中国科学A辑(英文版)》2006,49(3):398-409
In this paper, by the Gelfand representation theory and the Silov idempotents theorem, we first obtain a central decomposition theorem related to a unital semi-simple n-homogeneous Banach algebra, and then give a similarity classification of two strongly irreducible Cowen-Douglas operators using this theorem. 相似文献