全文获取类型
收费全文 | 433篇 |
免费 | 19篇 |
国内免费 | 33篇 |
专业分类
化学 | 1篇 |
力学 | 1篇 |
综合类 | 7篇 |
数学 | 436篇 |
物理学 | 40篇 |
出版年
2024年 | 2篇 |
2023年 | 6篇 |
2022年 | 10篇 |
2021年 | 9篇 |
2020年 | 15篇 |
2019年 | 11篇 |
2018年 | 20篇 |
2017年 | 7篇 |
2016年 | 3篇 |
2015年 | 5篇 |
2014年 | 11篇 |
2013年 | 59篇 |
2012年 | 8篇 |
2011年 | 10篇 |
2010年 | 13篇 |
2009年 | 28篇 |
2008年 | 28篇 |
2007年 | 21篇 |
2006年 | 20篇 |
2005年 | 28篇 |
2004年 | 22篇 |
2003年 | 21篇 |
2002年 | 18篇 |
2001年 | 22篇 |
2000年 | 20篇 |
1999年 | 11篇 |
1998年 | 12篇 |
1997年 | 13篇 |
1996年 | 9篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
排序方式: 共有485条查询结果,搜索用时 46 毫秒
101.
《代数通讯》2013,41(6):2407-2418
Let X be a left R-module. We characterize when the direct sum of two X-extending modules is X-extending via essential injectivity and pseudo injectivity of modules. As a corollary, we show that if extending modules M 1 and M 2 are relatively essentially injective and M 1 is pseudo-M 2-injective (or M 2 is pseudo-M 1-injective) then M 1 ⊕ M 2 is extending. Also we characterize when the direct sum of two CESS-modules is CESS. Some characterizations of almost Noetherian rings are also given by relative (quasi-) continuity of left R-modules. 相似文献
102.
《代数通讯》2013,41(2):789-798
We introduce the concept of decimal extension of the additive group of integers. We characterize these extensions as the linearly ordered abelian groups containing at least one Archimedean element. Finally, we study the additive group of rationals and its subgroups as particular cases of decimal extension. 相似文献
103.
Juan González-Férez 《代数通讯》2013,41(3):1078-1087
Let k be a field and X a set and P be a set of words over X. Consider the free nonunital k-algebra over X generated by the nonempty words over X and let R be the quotient of this algebra modulo the ideal generated by the words in P. R is called a “nonunital monomial algebra”. A right R-module M is said to be “firm” if M? R R → M given by m ? r? mr is an isomorphism. In this article we prove that if R is a nonunital monomial algebra, the category of firm modules is Grothendieck. 相似文献
104.
Two words are called k-abelian equivalent, if they share the same multiplicities for all factors of length at most k. We present an optimal linear time algorithm for identifying all occurrences of factors in a text that are k-abelian equivalent to some pattern P. Moreover, an optimal algorithm for finding the largest k for which two words are k-abelian equivalent is given. Solutions for online versions of the k-abelian pattern matching problem are also proposed. 相似文献
105.
We show that complex multiplication on Abelian varieties is equivalent to the existence of a constant rational Kähler metric. We give a sufficient condition for a mirror of an Abelian variety of CM-type to be of CM-type. We also study the relationship between complex multiplication and rationality of a toroidal lattice vertex algebra. 相似文献
106.
L. R. Vermani 《代数通讯》2013,41(8):3259-3266
We compute subgroups of the normal subgroup R of a free group F determined by certain ideals contained in the augmentation ideal Δ(R) and then prove certain subquotients of R to be free Abelian. 相似文献
107.
108.
In this paper, we prove a kind of Abelian theorem for a class of stochastic volatility models (X,V) where both the state process X and the volatility process V may have jumps. Our results relate the asymptotic behavior of the characteristic function of XΔ for some Δ>0 in a stationary regime to the Blumenthal–Getoor indexes of the Lévy processes driving the jumps in X and V. The results obtained are used to construct consistent estimators for the above Blumenthal–Getoor indexes based on low-frequency observations of the state process X. We derive convergence rates for the corresponding estimator and show that these rates cannot be improved in general. 相似文献
109.
洪晓春 《数学的实践与认识》2010,40(3)
利用Picard-Fuchs方程法及Riccati方程法,研究了一类二次可逆系统在任意n次多项式扰动下Abel积分零点个数的上界问题,得到了当n≥4时,上界为10n+[n/2]-1. 相似文献
110.
将Minkowski关于有限整数矩阵群的著名结果推广到一般的环上,主要结果是证明了:对任意环R,如果R的加法群为有限生成的自由Abel群,则R的所有乘法可逆元构成的群U(R)中的有限子群精确到同构只有有限多个. 相似文献