全文获取类型
收费全文 | 4477篇 |
免费 | 198篇 |
国内免费 | 19篇 |
专业分类
化学 | 3285篇 |
晶体学 | 51篇 |
力学 | 67篇 |
数学 | 536篇 |
物理学 | 755篇 |
出版年
2023年 | 22篇 |
2022年 | 35篇 |
2021年 | 93篇 |
2020年 | 92篇 |
2019年 | 100篇 |
2018年 | 58篇 |
2017年 | 60篇 |
2016年 | 139篇 |
2015年 | 121篇 |
2014年 | 149篇 |
2013年 | 248篇 |
2012年 | 308篇 |
2011年 | 320篇 |
2010年 | 213篇 |
2009年 | 230篇 |
2008年 | 300篇 |
2007年 | 292篇 |
2006年 | 254篇 |
2005年 | 216篇 |
2004年 | 198篇 |
2003年 | 166篇 |
2002年 | 169篇 |
2001年 | 135篇 |
2000年 | 120篇 |
1999年 | 90篇 |
1998年 | 61篇 |
1997年 | 42篇 |
1996年 | 64篇 |
1995年 | 41篇 |
1994年 | 43篇 |
1993年 | 35篇 |
1992年 | 33篇 |
1991年 | 19篇 |
1990年 | 31篇 |
1989年 | 18篇 |
1988年 | 22篇 |
1987年 | 16篇 |
1986年 | 19篇 |
1985年 | 23篇 |
1984年 | 20篇 |
1983年 | 17篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1980年 | 9篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1974年 | 4篇 |
1973年 | 7篇 |
排序方式: 共有4694条查询结果,搜索用时 139 毫秒
11.
Jerónimo Rodríguez 《Comptes Rendus Mathematique》2004,339(6):445-450
In the present Note we introduce an extension of the conservative space–time mesh refinement method presented by Fouquet et al. We also propose a post-treatment of the solution that reduces the spurious phenomena due to the non-conformity between the time meshes. A reinterpretation of the equations in terms of new unknowns leads to a new scheme with second order consistent coupling equations. Numerical experiments in 2D and a plane wave analysis for the 1D model show that the method is second order accurate for an arbitrary refinement. To cite this article: J. Rodríguez, C. R. Acad. Sci. Paris, Ser. I 339 (2004). 相似文献
12.
13.
Ricaurte Rodríguez Manuel Nogueras Justo Cobo John N. Low Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(7):o376-o378
Molecules of the title compound, C12H13ClN4, are linked by two independent N—H...N hydrogen bonds into a chain of edge‐fused R22(8) rings. The significance of this study lies in its attempt to rationalize the patterns of supramolecular aggregation in the title compound and in a range of analogous 4,6‐disubstituted 2‐aminopyrimidines. 相似文献
14.
C. Foces‐Foces M. Lpez‐Rodríguez C. Prez 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(2):o95-o97
The title compound, C12H21NO3, crystallizes in two polymorphic forms, viz. the tetragonal form described here and the monoclinic form described previously [Foces‐Foces, López‐Rodríguez, Pérez, Martín & Pérez‐Hernández (2007). Cryst. Growth Des. 7 , 905–911]. The differences in the conformations of the hydroxymethyl and methylaminocarbonyl substituents have important consequences in the hydrogen‐bond interaction motifs and, therefore, in the packing arrangements. These forms are concomitant polymorphs with melting points differing by 3 K. 相似文献
15.
16.
In this paper, a generalized anti–maximum principle for the second order differential operator with potentials is proved. As an application, we will give a monotone iterative scheme for periodic solutions of nonlinear second order equations. Such a scheme involves the Lp norms of the growth, 1 ≤ p ≤ ∞, while the usual one is just the case p = ∞. 相似文献
17.
E. Liénard G. Ban J. Blieck D. Durand F. Duval X. Fléchard M. Herbane M. Labalme Y. Lemière F. Mauger A. Méry O. Naviliat-Cuncic D. Rodríguez J. C. Thomas 《Hyperfine Interactions》2006,172(1-3):29-33
We report on the status of the LPCTrap experiment, devoted to measure the β–ν angular correlation in the pure Gamow–Teller
decay of 6He. This measurement is motivated by the search for the presence of tensor type contributions to the weak interaction. The
6He ions are confined in a novel transparent Paul trap. The β particles and the recoil ions are detected in coincidence to
deduce the angular correlation parameter. The commissioning run performed in 2005 has given the proof of principle of this
experiment. Up to 105 coincidences were recorded during a second run in 2006. 相似文献
18.
19.
We study the evolution of radiating and viscous fluid spheres assuming an additional homothetic symmetry on the spherically symmetric space-time. We match a very simple solution to the symmetry equations with the exterior one (Vaidya). We then obtain a system of two ordinary differential equations which rule the dynamics, and find a self-similar collapse which is shear-free and with a barotropic equation of state. Considering a huge set of initial self-similar dynamics states, we work out a model with an acceptable physical behavior. 相似文献
20.
Rodolfo Rodríguez 《Numerical Methods for Partial Differential Equations》1994,10(5):625-635
In this article, Zienkiewicz-Zhu estimator is analyzed for the piecewise linear finite element approximate solution of an elliptic problem. The estimator is proved to be equivalent to the error for the Poisson equation with a homogeneous Dirichlet boundary condition for any triangular regular mesh. No assumptions are needed about the regularity of the solution (i.e., solutions with corner singularities are not excluded). The estimator is also proved to be asymptotically exact on subdomains where the solution is smooth when parallel meshes are used. Therefore, its behavior is similar to that of other well-known estimators. © 1994 John Wiley & Sons, Inc. 相似文献