全文获取类型
收费全文 | 17027篇 |
免费 | 1348篇 |
国内免费 | 1157篇 |
专业分类
化学 | 9909篇 |
晶体学 | 99篇 |
力学 | 69篇 |
综合类 | 54篇 |
数学 | 7599篇 |
物理学 | 1802篇 |
出版年
2024年 | 31篇 |
2023年 | 304篇 |
2022年 | 232篇 |
2021年 | 250篇 |
2020年 | 467篇 |
2019年 | 530篇 |
2018年 | 523篇 |
2017年 | 340篇 |
2016年 | 526篇 |
2015年 | 643篇 |
2014年 | 896篇 |
2013年 | 1395篇 |
2012年 | 880篇 |
2011年 | 1162篇 |
2010年 | 999篇 |
2009年 | 1070篇 |
2008年 | 1191篇 |
2007年 | 1082篇 |
2006年 | 917篇 |
2005年 | 641篇 |
2004年 | 609篇 |
2003年 | 572篇 |
2002年 | 464篇 |
2001年 | 337篇 |
2000年 | 339篇 |
1999年 | 336篇 |
1998年 | 294篇 |
1997年 | 209篇 |
1996年 | 267篇 |
1995年 | 287篇 |
1994年 | 253篇 |
1993年 | 191篇 |
1992年 | 182篇 |
1991年 | 99篇 |
1990年 | 84篇 |
1989年 | 81篇 |
1988年 | 61篇 |
1987年 | 45篇 |
1986年 | 44篇 |
1985年 | 94篇 |
1984年 | 86篇 |
1983年 | 52篇 |
1982年 | 84篇 |
1981年 | 62篇 |
1980年 | 52篇 |
1979年 | 60篇 |
1978年 | 55篇 |
1977年 | 38篇 |
1976年 | 44篇 |
1975年 | 22篇 |
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
991.
We describe the possible restrictions of the cotangent bundle to an elliptic curve . We apply this in positive characteristic to the computation of the Hilbert-Kunz function of a homogeneous R+-primary ideal in the graded section ring . 相似文献
992.
993.
On the concepts of intertwining operator and tensor product module in vertex operator algebra theory
Yi-Zhi Huang James Lepowsky Haisheng Li Lin Zhang 《Journal of Pure and Applied Algebra》2006,204(3):507-535
We produce counterexamples to show that in the definition of the notion of intertwining operator for modules for a vertex operator algebra, the commutator formula cannot in general be used as a replacement axiom for the Jacobi identity. We further give a sufficient condition for the commutator formula to imply the Jacobi identity in this definition. Using these results we illuminate the crucial role of the condition called the “compatibility condition” in the construction of the tensor product module in vertex operator algebra theory, as carried out in work of Huang and Lepowsky. In particular, we prove by means of suitable counterexamples that the compatibility condition was indeed needed in this theory. 相似文献
994.
We develop general results on centroids of Lie algebras and apply them to determine the centroid of extended affine Lie algebras, loop-like and Kac-Moody Lie algebras, and Lie algebras graded by finite root systems. 相似文献
995.
D.P. Patil 《Journal of Pure and Applied Algebra》2006,205(2):266-278
In this article we characterize noetherian local one-dimensional analytically irreducible and residually rational domains (R,mR) which are non-Gorenstein, the non-negative integer is equal to τR-1 and ?(R/(C+xR))=2, where τR is the Cohen-Macaulay type of R, C is the conductor of R in the integral closure of R in its quotient field Q(R) and xR is a minimal reduction of m by giving some conditions on the numerical semi-group v(R) of R. 相似文献
996.
Achim Kehrein 《Journal of Pure and Applied Algebra》2006,205(2):279-295
This paper presents several algorithms that compute border bases of a zero-dimensional ideal. The first relates to the FGLM algorithm as it uses a linear basis transformation. In particular, it is able to compute border bases that do not contain a reduced Gröbner basis. The second algorithm is based on a generic algorithm by Bernard Mourrain originally designed for computing an ideal basis that need not be a border basis. Our fully detailed algorithm computes a border basis of a zero-dimensional ideal from a given set of generators. To obtain concrete instructions we appeal to a degree-compatible term ordering σ and hence compute a border basis that contains the reduced σ-Gröbner basis. We show an example in which this computation actually has advantages over Buchberger's algorithm. Moreover, we formulate and prove two optimizations of the Border Basis Algorithm which reduce the dimensions of the linear algebra subproblems. 相似文献
997.
Given an Ext-injective stratifying system of Λ-modules satisfying that the projective dimension of Y is finite, we prove that the finitistic dimension of the algebra Λ is equal to the finitistic dimension of the category . Moreover, using the theory of stratifying systems we obtain bounds for the finitistic dimension of Λ. In particular, we get the optimal bound 2n-2 for the finitistic dimension of a standardly stratified algebra with n simples. 相似文献
998.
Shokrollah Salarian Sean Sather-Wagstaff Siamak Yassemi 《Journal of Pure and Applied Algebra》2006,207(1):99-108
Let (R,m) be a Noetherian local ring of depth d and C a semidualizing R-complex. Let M be a finite R-module and t an integer between 0 and d. If the GC-dimension of M/aM is finite for all ideals a generated by an R-regular sequence of length at most d−t then either the GC-dimension of M is at most t or C is a dualizing complex. Analogous results for other homological dimensions are also given. 相似文献
999.
We prove various properties of varieties of special linear systems on double coverings of hyperelliptic curves. We show and determine the irreducibility, generically reducedness and singular loci of the variety for bi-elliptic curves and double coverings of genus two curves. Similar results for double coverings of hyperelliptic curves of genus h≥3 are also presented. 相似文献
1000.
Jonas Söderberg 《Journal of Pure and Applied Algebra》2006,207(2):417-432
We prove that a sequence of positive integers (h0,h1,…,hc) is the Hilbert function of an artinian level module of embedding dimension two if and only if hi−1−2hi+hi+1≤0 for all 0≤i≤c, where we assume that h−1=hc+1=0. This generalizes a result already known for artinian level algebras. We provide two proofs, one using a deformation argument, the other a construction with monomial ideals. We also discuss liftings of artinian modules to modules of dimension one. 相似文献