全文获取类型
收费全文 | 77713篇 |
免费 | 23282篇 |
国内免费 | 18362篇 |
专业分类
化学 | 48887篇 |
晶体学 | 943篇 |
力学 | 5355篇 |
综合类 | 67篇 |
数学 | 10321篇 |
物理学 | 53784篇 |
出版年
2024年 | 455篇 |
2023年 | 659篇 |
2022年 | 645篇 |
2021年 | 537篇 |
2020年 | 793篇 |
2019年 | 1317篇 |
2018年 | 1308篇 |
2017年 | 1948篇 |
2016年 | 2056篇 |
2015年 | 2271篇 |
2014年 | 2080篇 |
2013年 | 3854篇 |
2012年 | 4142篇 |
2011年 | 6957篇 |
2010年 | 9756篇 |
2009年 | 9996篇 |
2008年 | 3217篇 |
2007年 | 2707篇 |
2006年 | 2425篇 |
2005年 | 2947篇 |
2004年 | 4286篇 |
2003年 | 3271篇 |
2002年 | 3081篇 |
2001年 | 3320篇 |
2000年 | 2367篇 |
1999年 | 2613篇 |
1998年 | 2252篇 |
1997年 | 1993篇 |
1996年 | 2322篇 |
1995年 | 2788篇 |
1994年 | 2815篇 |
1993年 | 3047篇 |
1992年 | 2684篇 |
1991年 | 2287篇 |
1990年 | 1950篇 |
1989年 | 2039篇 |
1988年 | 1875篇 |
1987年 | 1128篇 |
1986年 | 1200篇 |
1985年 | 861篇 |
1984年 | 980篇 |
1982年 | 894篇 |
1981年 | 730篇 |
1980年 | 769篇 |
1979年 | 528篇 |
1978年 | 531篇 |
1977年 | 636篇 |
1976年 | 1043篇 |
1973年 | 437篇 |
1972年 | 532篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
The notion of Kuratowski convergence is applied to describe a kind of convergence in the context of holomorphic functions. We associate it to a convenient topology, explore its relation with the compact-open topology, thus providing a new set theoretic point of view of this classic topology, and present it in the framework of set-valued mappings. 相似文献
63.
We consider a spinning charge coupled to the Maxwell field. Through the appropriate symmetry in the initial conditions the charge remains at rest. We establish that any time-dependent finite energy solution converges to a sum of a soliton wave and an outgoing free wave. The convergence holds in global energy norm. Under a small constant external magnetic field the soliton manifold is stable in local energy seminorms and the evolution of the angular velocity is guided by an effective finite-dimensional dynamics. The proof uses a non-autonomous integral inequality method. 相似文献
64.
65.
We give a Gray code and constant average time generating algorithm for derangements, i.e., permutations with no fixed points. In our Gray code, each derangement is transformed into its successor either via one or two transpositions or a rotation of three elements. We generalize these results to permutations with number of fixed points bounded between two constants. 相似文献
66.
We prove here that the surface of the regular icosahedron can be triangulated with 8
non-obtuse and with 12 acute triangles. We also show these numbers to be smallest
possible. 相似文献
67.
Robert Krauthgamer Nathan Linial Avner Magen 《Discrete and Computational Geometry》2004,31(3):339-356
The extensive study of metric spaces and their embeddings
has so far focused on embeddings that preserve pairwise distances.
A very intriguing concept introduced by Feige
allows us to quantify the extent to which larger
structures are preserved by a given embedding.
We investigate this concept, focusing on several major graph families
such as paths, trees, cubes, and expanders.
We find some similarities to the regular (pairwise) distortion,
as well as some striking differences. 相似文献
68.
S. Aravinda N. Shamala Rituparna S. Roy P Balaram 《Journal of Chemical Sciences》2003,115(5-6):373-400
An overview of the use of non-protein amino acids in the design of conformationally well-defined peptides, based on work from
the author’s laboratory, is discussed. The crystal structures of several designed oligopeptides illustrate the useα-aminoisobutyric acid (Aib) in the construction of helices, D-amino acids in the design of helix termination segments andDPro-Xxx segments for nucleating ofβ-hairpin structures.β- andγ-amino acid residues have been used to expand the range of designed polypeptide structures.
Dedicated to Professor C N R Rao on his 70th birthday 相似文献
69.
The paper discusses the relationship between weights and control vertices of two rational NURBS curves of degree two or three with all weights larger than zero when they represent the same curve parametrically and geometrically, and gives sufficient and necessary conditions for coincidence of two rational NURBS curves in non-degeneracy case. 相似文献
70.
Let Cld
AW
(X) be the hyperspace of nonempty closed subsets of a normed linear space X with the Attouch–Wets topology. It is shown that the space Cld
AW
(X) and its various subspaces are AR's. Moreover, if X is an infinite-dimensional Banach space with weight w(X) then Cld
AW
(X) is homeomorphic to a Hilbert space with weight 2
w(X). 相似文献