全文获取类型
收费全文 | 7510篇 |
免费 | 188篇 |
国内免费 | 79篇 |
专业分类
化学 | 684篇 |
晶体学 | 33篇 |
力学 | 60篇 |
综合类 | 10篇 |
数学 | 5723篇 |
物理学 | 1267篇 |
出版年
2023年 | 21篇 |
2022年 | 24篇 |
2021年 | 24篇 |
2020年 | 23篇 |
2019年 | 207篇 |
2018年 | 206篇 |
2017年 | 100篇 |
2016年 | 83篇 |
2015年 | 66篇 |
2014年 | 212篇 |
2013年 | 430篇 |
2012年 | 210篇 |
2011年 | 376篇 |
2010年 | 345篇 |
2009年 | 587篇 |
2008年 | 634篇 |
2007年 | 643篇 |
2006年 | 480篇 |
2005年 | 354篇 |
2004年 | 305篇 |
2003年 | 274篇 |
2002年 | 211篇 |
2001年 | 192篇 |
2000年 | 165篇 |
1999年 | 141篇 |
1998年 | 138篇 |
1997年 | 83篇 |
1996年 | 153篇 |
1995年 | 136篇 |
1994年 | 154篇 |
1993年 | 122篇 |
1992年 | 106篇 |
1991年 | 56篇 |
1990年 | 54篇 |
1989年 | 49篇 |
1988年 | 27篇 |
1987年 | 35篇 |
1986年 | 33篇 |
1985年 | 34篇 |
1984年 | 43篇 |
1983年 | 20篇 |
1982年 | 33篇 |
1981年 | 41篇 |
1980年 | 33篇 |
1979年 | 24篇 |
1978年 | 25篇 |
1977年 | 26篇 |
1976年 | 24篇 |
1974年 | 5篇 |
1973年 | 4篇 |
排序方式: 共有7777条查询结果,搜索用时 15 毫秒
71.
Global Existence and Exponential Stability of Smooth Solutions to a Full Hydrodynamic Model to Semiconductors 总被引:1,自引:0,他引:1
We study a full hydrodynamic semiconductor model in multi-space dimension. The global existence of smooth solutions is established
and the exponential stability of the solutions as is investigated.
Received November 14, 2000; in revised form March 25, 2002 Published online August 5, 2002 相似文献
72.
Cyrille Ospel 《Journal of Pure and Applied Algebra》2002,173(3):315-337
For a commutative algebra the shuffle product is a morphism of complexes. We generalize this result to the quantum shuffle product, associated to a class of non-commutative algebras (for example all the Hopf algebras). As a first application we show that the Hochschild-Serre identity is the dual statement of our result. In particular, we extend this identity to Hopf algebras. Secondly, we clarify the construction of a class of quasi-Hopf algebras. 相似文献
73.
Raiko P. Zaikov 《Letters in Mathematical Physics》1994,32(4):283-297
Higher spin extensions of the non-Abelian gauge symmetries for the classical WZNW model are considered. Both linear and nonlinear realizations of the extended affine Kac-Moody algebra are obtained. It is a characteristic property of the WZNW model that it admits a higher spin linear realization of the extended affine Kac-Moody algebra which is equivalent to the corresponding higher spin nonlinear realization of the same algebra. However, in both cases, the higher spin Noether currents do not span an invariant space with respect to their generating transformations. Here, the current space is extended to an invariant space which allows us to gauge the symmetry.Supported by Bulgarian Foundation on Fundamental Research under contract Ph-318/93-95. 相似文献
74.
Gabriel Picavet 《Journal of Pure and Applied Algebra》2002,174(2):163-185
We define and study algebraically flat algebras in order to have a better understanding of algebraically projective algebras of finite type (the projective algebras of literature). A close examination of the differential properties of these algebras leads to our main structure theorem. As a corollary, we get that an algebraically projective algebra of finite type over a field is either a polynomial ring or the affine algebra of a complete intersection. 相似文献
75.
M. A. Macrì C. Del Gratta L. Di Donato S. Di Luzio G. L. Romani S. Della Penna A. Pasquarelli 《Il Nuovo Cimento D》1994,16(5):425-432
Summary A preliminary study is here reported on a new potential marker for biomagnetic measurements. The marker consists of superparamagnetic
polymer microspheres which were detected in the presence of external steady magnetic fields by means of an r.f.-SQUID magnetometer.
The particles were prepared in samples differing in the concentration value and immersed in a homogeneous magnetic field of
variable intensity. A simple model was taken into account for the distribution of the microspheres in the samples, so that
the theoretical values were compared to the marker field values measured by the biomagnetic sensor. The overall sensitivity
of the experimental apparatus and the minimum concentration value of the marker were then estimated. 相似文献
76.
Hideaki Ishikawa 《Archiv der Mathematik》2002,79(6):439-448
In this paper we introduce a certain sum by using Dirichlet characters. We investigate the Riesz mean of the sum using the
analytic properties of the MultipleL-function systematically.
Eine überarbeitete Fassung ging am 6. 8. 2001 ein 相似文献
77.
Motivated by the work of Crapo and Rota [6] on the lifting of a projective complex, we introduce a class of invariant operations associated to integral-weighted graphs, which we call graphical operations. Such operations generalize the sixth harmonic of a quadranguler set on a projective line. We determine the expansion of the graphical operations in terms of multi-linear bracket polynomials in a Grassmann-Cayley algebra. Reducibility and compositions of such invariant operations are also investigated with a number of examples.Supported by Courant Instructorship, New York University. 相似文献
78.
Alexander O. Smirnov 《Letters in Mathematical Physics》2006,76(2-3):297-316
We find a new class of Fuchsian equations, with algebro-geometric solutions associated to a hyperelliptic curve. A method for calculating its arithmetic genus and branching points is suggested. Numerous examples are given. 相似文献
79.
Given an integer n ≥ 2, let λ(n) := (log n)/(log γ(n)), where γ(n) = Π
p|n p, stand for the index of composition of n, with λ(1) = 1. We study the distribution function of (λ(n) – 1) log n as n runs through particular sets of integers, such as the shifted primes, the values of a given irreducible cubic polynomial
and the shifted powerful numbers.
Research supported in part by a grant from NSERC.
Research supported by the Applied Number Theory Research Group of the Hungarian Academy of Science and by a grant from OTKA.
Professor M.V. Subbarao passed away on February 15, 2006.
Received: 3 March 2006 Revised: 28 October 2006 相似文献
80.
Kim Dang Phung 《Journal of Differential Equations》2007,240(1):92-124
Using Fourier integral operators with special amplitude functions, we analyze the stabilization of the wave equation in a three-dimensional bounded domain on which exists a trapped ray bouncing up and down infinitely between two parallel parts of the boundary. 相似文献