全文获取类型
收费全文 | 7724篇 |
免费 | 162篇 |
国内免费 | 31篇 |
专业分类
化学 | 186篇 |
晶体学 | 3篇 |
力学 | 97篇 |
数学 | 7104篇 |
物理学 | 362篇 |
综合类 | 165篇 |
出版年
2023年 | 9篇 |
2022年 | 14篇 |
2021年 | 12篇 |
2020年 | 17篇 |
2019年 | 166篇 |
2018年 | 213篇 |
2017年 | 116篇 |
2016年 | 71篇 |
2015年 | 90篇 |
2014年 | 213篇 |
2013年 | 392篇 |
2012年 | 285篇 |
2011年 | 461篇 |
2010年 | 358篇 |
2009年 | 531篇 |
2008年 | 563篇 |
2007年 | 584篇 |
2006年 | 414篇 |
2005年 | 312篇 |
2004年 | 225篇 |
2003年 | 178篇 |
2002年 | 159篇 |
2001年 | 173篇 |
2000年 | 167篇 |
1999年 | 208篇 |
1998年 | 176篇 |
1997年 | 144篇 |
1996年 | 162篇 |
1995年 | 165篇 |
1994年 | 177篇 |
1993年 | 139篇 |
1992年 | 130篇 |
1991年 | 80篇 |
1990年 | 98篇 |
1989年 | 93篇 |
1988年 | 63篇 |
1987年 | 59篇 |
1986年 | 48篇 |
1985年 | 59篇 |
1984年 | 59篇 |
1983年 | 27篇 |
1982年 | 63篇 |
1981年 | 46篇 |
1980年 | 48篇 |
1979年 | 26篇 |
1978年 | 39篇 |
1977年 | 35篇 |
1976年 | 27篇 |
1975年 | 9篇 |
1973年 | 7篇 |
排序方式: 共有7917条查询结果,搜索用时 15 毫秒
61.
62.
Bo Göran Johansson 《Historia Mathematica》2011,38(3):338-367
The algorithms used in Arabic and medieval European mathematics for extracting cube roots are studied with respect to algebraic structure and use of external memory (dust board, table, paper). They can be separated into two distinct groups. One contains methods used in the eastern regions from the 11th century, closely connected to Chinese techniques, and very uniform in structure. The other group, showing much wider variation, contains early Indian methods and techniques developed in central and western parts of the Arabic areas and in Europe. This study supports hypotheses previously formulated by Luckey and Chemla on an early scientific connection between China and Persia. 相似文献
63.
Yoshiyuki Kagei 《Journal of Differential Equations》2011,251(11):3248-3295
The initial boundary value problem for the compressible Navier-Stokes equation is considered in an infinite layer of Rn. It is proved that if n?3, then strong solutions to the compressible Navier-Stokes equation around parallel flows exist globally in time for sufficiently small initial perturbations, provided that the Reynolds and Mach numbers are sufficiently small. The proof is given by a variant of the Matsumura-Nishida energy method based on a decomposition of solutions associated with a spectral property of the linearized operator. 相似文献
64.
We study three types of quotient maps of frames which are closely related to C- and C?-quotient maps. We call them C1-, strong C1-, and uplifting quotient maps. C1-quotient maps are precisely those whose induced ring homomorphisms contract maximal ideals to maximal ideals. We show that every homomorphism onto a frame is a C1-, a strong C1-, or an uplifting quotient map iff the frame is pseudocompact, compact, or almost compact and normal, respectively. These quotient maps are used to characterize normality and also certain weaker forms of normality in a manner akin to the characterization of normal frames as those for which every closed quotient map is a C-quotient map. Under certain conditions, we show that the Stone extension of a quotient map is C1-, strongly C1- or uplifting if the map has the corresponding property. 相似文献
65.
Igor Leite Freire Antonio Cândido Faleiros 《Nonlinear Analysis: Theory, Methods & Applications》2011,74(11):3478-3486
Using the classical Lie method we obtain the full Lie point symmetry group of the Aronsson equation in two independent variables. Some group invariant solutions of this equation are found and a conjecture on the Lie point symmetry group of the Aronsson equation in Rn is presented. 相似文献
66.
67.
68.
Nicholas J. Daras 《Numerical Algorithms》1999,20(4):285-301
Padé-type approximation is the rational function analogue of Taylor’s polynomial approximation to a power series. A general
method for obtaining Padé-type approximants to Fourier series expansions of harmonic functions is defined. This method is
based on the Newton-Cotes and Gauss quadrature formulas. Several concrete examples are given and the convergence behavior
of a sequence of such approximants is studied.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
69.
B. Dacorogna I. Fonseca J. Malý K. Trivisa 《Calculus of Variations and Partial Differential Equations》1999,9(3):185-206
The integral representation for the relaxation of a class of energy functionals where the admissible fields are constrained
to remain on a
-dimensional manifold is obtained. If is a continuous function satisfying for and for all then where is open, bounded, and is the tangential quasiconvexification of f at
belong to the tangent space to at
Received October 10, 1998 / Accepted December 1, 1998 相似文献
70.