全文获取类型
收费全文 | 7766篇 |
免费 | 427篇 |
国内免费 | 912篇 |
专业分类
化学 | 140篇 |
力学 | 180篇 |
综合类 | 167篇 |
数学 | 7552篇 |
物理学 | 1066篇 |
出版年
2024年 | 11篇 |
2023年 | 98篇 |
2022年 | 123篇 |
2021年 | 143篇 |
2020年 | 167篇 |
2019年 | 213篇 |
2018年 | 226篇 |
2017年 | 227篇 |
2016年 | 205篇 |
2015年 | 140篇 |
2014年 | 256篇 |
2013年 | 1119篇 |
2012年 | 237篇 |
2011年 | 364篇 |
2010年 | 329篇 |
2009年 | 432篇 |
2008年 | 507篇 |
2007年 | 516篇 |
2006年 | 478篇 |
2005年 | 412篇 |
2004年 | 382篇 |
2003年 | 359篇 |
2002年 | 373篇 |
2001年 | 268篇 |
2000年 | 271篇 |
1999年 | 243篇 |
1998年 | 213篇 |
1997年 | 212篇 |
1996年 | 133篇 |
1995年 | 91篇 |
1994年 | 66篇 |
1993年 | 47篇 |
1992年 | 33篇 |
1991年 | 28篇 |
1990年 | 22篇 |
1989年 | 18篇 |
1988年 | 17篇 |
1987年 | 11篇 |
1986年 | 23篇 |
1985年 | 21篇 |
1984年 | 14篇 |
1983年 | 12篇 |
1982年 | 11篇 |
1981年 | 7篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1957年 | 3篇 |
1936年 | 5篇 |
排序方式: 共有9105条查询结果,搜索用时 15 毫秒
141.
William Slofstra 《Advances in Mathematics》2012,229(2):968-983
Braverman and Finkelberg have recently proposed a conjectural analogue of the geometric Satake isomorphism for untwisted affine Kac–Moody groups. As part of their model, they conjecture that (at dominant weights) Lusztig's q-analog of weight multiplicity is equal to the Poincare series of the principal nilpotent filtration of the weight space, as occurs in the finite-dimensional case. We show that the conjectured equality holds for all affine Kac–Moody algebras if the principal nilpotent filtration is replaced by the principal Heisenberg filtration. The main body of the proof is a Lie algebra cohomology vanishing result. We also give an example to show that the Poincare series of the principal nilpotent filtration is not always equal to the q-analog of weight multiplicity. Finally, we give some partial results for indefinite Kac–Moody algebras. 相似文献
142.
Let A be a basic hereditary artin algebra and R = A Q be the trivial extension of A by its minimal injective cogenerator Q. We construct some right (left) almost split morphisms and irreducible morphisms in modR through the corresponding morphisms in modA. Furthermore, we can determine its almost split sequences in modR. 相似文献
143.
Sheldon P. Gordon 《International Journal of Mathematical Education in Science & Technology》2017,48(3):455-473
This article takes a closer look at the problem of approximating the exponential and logarithmic functions using polynomials. Either as an alternative to or a precursor to Taylor polynomial approximations at the precalculus level, interpolating polynomials are considered. A measure of error is given and the behaviour of the error function is analysed. The results of interpolating polynomials are compared with those of Taylor polynomials. 相似文献
144.
LAO HUI-XUE 《东北数学》2012,28(2)
Under the assumption of sixth power large sieve mean-value of Dirichlet L-function,we improve Bombieri's theorem in short intervals by virtue of the large sieve method and Heath-Brown's identity. 相似文献
145.
Hai Q. Dinh Xiaoqiang Wang Hongwei Liu Songsak Sriboonchitta 《Discrete Mathematics》2019,342(5):1456-1470
Let be an odd prime, , be positive integers, be nonzero elements of the finite field such that . In this paper, we show that, for any positive integer , the Hamming distances of all repeated-root -constacyclic codes of length can be determined by those of certain simple-root -constacyclic codes of length . Using this result, Hamming distances of all constacyclic codes of length are obtained. As an application, we identify all MDS -constacyclic codes of length . 相似文献
146.
147.
<正>Coarse-graining of some sort is a fundamental and unavoidable step in any attempt to derive the classical mechanical behavior from the quantum formalism.We utilize the two-mode Bose-Hubbard model to illustrate how different coarse-grained systems can be naturally associated with a fixed quantum system if it is compatible with different dynamical algebras.Alternative coarse-grained systems generate different evolutions of the same physical quantities,and the difference becomes negligible only in the appropriate macro-limit. 相似文献
149.
Jordan operator algebras are norm‐closed spaces of operators on a Hilbert space with for all . In two recent papers by the authors and Neal, a theory for these spaces was developed. It was shown there that much of the theory of associative operator algebras, in particular, surprisingly much of the associative theory from several recent papers of the first author and coauthors, generalizes to Jordan operator algebras. In the present paper we complete this task, giving several results which generalize the associative case in these papers, relating to unitizations, real positivity, hereditary subalgebras, and a couple of other topics. We also solve one of the three open problems stated at the end of our earlier joint paper on Jordan operator algebras. 相似文献
150.