全文获取类型
收费全文 | 14586篇 |
免费 | 2840篇 |
国内免费 | 1465篇 |
专业分类
化学 | 3027篇 |
晶体学 | 182篇 |
力学 | 2658篇 |
综合类 | 189篇 |
数学 | 2537篇 |
物理学 | 10298篇 |
出版年
2024年 | 16篇 |
2023年 | 147篇 |
2022年 | 266篇 |
2021年 | 347篇 |
2020年 | 446篇 |
2019年 | 350篇 |
2018年 | 366篇 |
2017年 | 478篇 |
2016年 | 581篇 |
2015年 | 518篇 |
2014年 | 807篇 |
2013年 | 1149篇 |
2012年 | 860篇 |
2011年 | 974篇 |
2010年 | 890篇 |
2009年 | 944篇 |
2008年 | 955篇 |
2007年 | 911篇 |
2006年 | 919篇 |
2005年 | 818篇 |
2004年 | 871篇 |
2003年 | 710篇 |
2002年 | 657篇 |
2001年 | 524篇 |
2000年 | 512篇 |
1999年 | 446篇 |
1998年 | 404篇 |
1997年 | 332篇 |
1996年 | 268篇 |
1995年 | 209篇 |
1994年 | 184篇 |
1993年 | 146篇 |
1992年 | 136篇 |
1991年 | 125篇 |
1990年 | 93篇 |
1989年 | 100篇 |
1988年 | 73篇 |
1987年 | 57篇 |
1986年 | 64篇 |
1985年 | 49篇 |
1984年 | 31篇 |
1983年 | 16篇 |
1982年 | 26篇 |
1981年 | 25篇 |
1980年 | 19篇 |
1979年 | 16篇 |
1978年 | 13篇 |
1977年 | 10篇 |
1976年 | 7篇 |
1957年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
971.
1IntroductionThegeometricphaseplaysanimportantroleinunderstandingsomeoftheoutstandingenigmasofquantummechanics,andithaspaidmu... 相似文献
972.
Zhi-Yong Jiao Jun-Mao Ma Ning Li Xia Fu 《International Journal of Theoretical Physics》2008,47(11):2841-2849
In this paper, we investigate entropy properties of the single-mode binomial field interacting with the two entangled two-level
atoms. It is found that the different initial conditions lead to the different evolutions of entropy of the binomial field. 相似文献
973.
974.
A unification of some factorization results regarding products of positive-definite matrices, commutators, and products of involutions is presented. This topic was first presented by Sourour for fields with, in the latter two classes, sufficiently many elements in terms of the order of the matrix being factored. The current presentation is valid for matrices over any field with at least four elements, and is independent of the order of the matrix being factored. 相似文献
975.
976.
We introduce a general method in order to construct the nonchiral fusion rules which determine the operator content of the operator product algebra for rational conformal field theories. We are particularly interested in the models of the complementary D-like solutions of the modular invariant partition functions with cyclic center Z
N
. We find that the nonchiral fusion rules have a Z
N
-grading structure. 相似文献
977.
The paper is devoted to peculiarities of the deformation quantization in the algebro-geometric context. A direct application of the formality theorem to an algebraic Poisson manifold gives a canonical sheaf of categories deforming coherent sheaves. The global category is very degenerate in general. Thus, we introduce a new notion of a semiformal deformation, a replacement in algebraic geometry of an actual deformation (versus a formal one). Deformed algebras obtained by semiformal deformations are Noetherian and have polynomial growth. We propose constructions of semiformal quantizations of projective and affine algebraic Poisson manifolds satisfying certain natural geometric conditions. Projective symplectic manifolds (e.g. K3 surfaces and Abelian varieties) do not satisfy our conditions, but projective spaces with quadratic Poisson brackets and Poisson–Lie groups can be semiformally quantized. 相似文献
978.
R. Valenzuela G. Alvarez H. Montiel M.P. Gutirrez M.E. Mata-Zamora F. Barrn A.Y. Snchez I. Betancourt R. Zamorano 《Journal of magnetism and magnetic materials》2008,320(14):1961-1965
A low-field non-resonant microwave absorption has recently been observed in a variety of magnetically ordered materials at low DC fields (−1000 Oe HDC+1000 Oe), which is known as low-field microwave absorption (LFA). It has been shown that LFA is essentially similar to giant magnetoimpedance (GMI), and clearly different from ferromagnetic resonance (FMR). LFA strongly depends on the anisotropy field of the sample. In contrast with FMR (which can be described as the homogeneous precession of spins in the saturated state), LFA can be thought as a spin rotation process occurring during the magnetic saturation. In this work, we present a detailed study of the basic features of LFA in several types of materials: ferrites and amorphous microwires and ribbons; in particular the effects sample shape, temperature up to the Curie transition, the influence of easy axis and the effects of annealings. These examples show that once LFA is fully understood, it can become a powerful characterization tool. 相似文献
979.
980.
岩土强度与变形关系的理论剖析 总被引:1,自引:0,他引:1
深入浅出地阐述了岩土强度与变形关系,并对一些令人困惑的问题进行了讨论和作出可能的解释。 相似文献