全文获取类型
收费全文 | 327篇 |
免费 | 2篇 |
国内免费 | 10篇 |
专业分类
化学 | 6篇 |
力学 | 8篇 |
综合类 | 2篇 |
数学 | 288篇 |
物理学 | 35篇 |
出版年
2023年 | 1篇 |
2022年 | 6篇 |
2021年 | 5篇 |
2020年 | 3篇 |
2019年 | 7篇 |
2018年 | 8篇 |
2017年 | 3篇 |
2016年 | 8篇 |
2015年 | 3篇 |
2014年 | 7篇 |
2013年 | 52篇 |
2012年 | 16篇 |
2011年 | 21篇 |
2010年 | 9篇 |
2009年 | 19篇 |
2008年 | 17篇 |
2007年 | 8篇 |
2006年 | 20篇 |
2005年 | 10篇 |
2004年 | 11篇 |
2003年 | 18篇 |
2002年 | 16篇 |
2001年 | 10篇 |
2000年 | 3篇 |
1999年 | 9篇 |
1998年 | 8篇 |
1997年 | 14篇 |
1996年 | 8篇 |
1994年 | 5篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有339条查询结果,搜索用时 743 毫秒
191.
This work is concerned with the consistency conditions for the equations in max plus algebra. The three classes of the max plus linear equations presented in the paper Shinzawa [Ultra discrete permanent and the consistency of max plus linear equations, Linear Algebra Appl. 506 (2016) 445–477] can be equivalently converted into the corresponding system of inequalities. The equivalence relation between ultra discrete permanent and maximum cycle mean is suggested. Thus, the necessary and sufficient conditions for solvability of the equations are obtained using the maximum cycle mean in this note. 相似文献
192.
《复变函数与椭圆型方程》2012,57(4):301-313
This article deals with the Runge type approximations problem, the solution of inhomogeneous system and the additive Cousin problem for Clifford-algebra-valued functions ?(x, y) which are regular with respect to x and real-analytic in y. Some main results concerning these three fundamental problems from complex analysis are proved for the class of functions mentioned above. 相似文献
193.
G.P.汤姆孙对电子衍射的实验研究 总被引:2,自引:0,他引:2
介绍了G.P.汤姆孙完成电子衍射实验,证明了德布罗意提出的物质波理论的研究经历从中可以看到注意研究选题的先进性,注重理论的先导作用和科学的研究方法的重要性。 相似文献
194.
在Fuzzy蕴涵代数(简称FI代数)上引入了MP理想与正规MP理想的概念并给出了它们的等价刻画;探讨了FI代数的MP理想、偏序理想和正规MP理想间的多种关系, 证明了一个正则FI代数是可交换FI代数当且仅当它的每个MP理想都是正规理想,也当且仅当{0}是正规MP理想. 相似文献
195.
从逻辑的角度,将非经典逻辑之一的格值逻辑引入概念格,建立了格值模糊形式背景,通过格结构来刻画对象与属性之间的模糊关系,证明了由蕴涵算子诱导的算子对是伽罗瓦连接,并讨论了相关的一些性质,进而给出了格值模糊概念格的构造算法.格值模糊概念格的建立为模糊性与不可比较性信息的处理提供了可靠的数学工具. 相似文献
196.
进一步讨论有1模格的等价定义问题,得到并证明了一个(2,2,0)型代数成为有1模格的一个充分必要条件.这样大大简化了有1模格的等价定义. 相似文献
197.
Let D be a commutative domain with field of fractions K, let A be a torsion-free D-algebra, and let B be the extension of A to a K-algebra. The set of integer-valued polynomials on A is , and the intersection of with is , which is a commutative subring of . The set may or may not be a ring, but it always has the structure of a left -module.A D-algebra A which is free as a D-module and of finite rank is called -decomposable if a D-module basis for A is also an -module basis for ; in other words, if can be generated by and A. A classification of such algebras has been given when D is a Dedekind domain with finite residue rings. In the present article, we modify the definition of -decomposable so that it can be applied to D-algebras that are not necessarily free by defining A to be -decomposable when is isomorphic to . We then provide multiple characterizations of such algebras in the case where D is a discrete valuation ring or a Dedekind domain with finite residue rings. In particular, if D is the ring of integers of a number field K, we show that an -decomposable algebra A must be a maximal D-order in a separable K-algebra B, whose simple components have as center the same finite unramified Galois extension F of K and are unramified at each finite place of F. Finally, when both D and A are rings of integers in number fields, we prove that -decomposable algebras correspond to unramified Galois extensions of K. 相似文献
198.
Martin Koutecký Jon Lee Viswanath Nagarajan Xiangkun Shen 《Operations Research Letters》2018,46(6):592-598
We consider the max-cut and max--cut problems under graph-based constraints. Our approach can handle any constraint specified using monadic second-order (MSO) logic on graphs of constant treewidth. We give a -approximation algorithm for this class of problems. 相似文献
199.
In mathematics education, it is important to assess valued practices such as problem solving and communication. Yet, often we assess students based on correct solutions over their problem solving strategies—strategies that can uncover important mathematical understanding. In this article, we first present a framework of competencies required for strategic reasoning to solve cognitively demanding algebra tasks and assessment tools to capture evidence of these competencies. Then, we qualitatively describe characteristics of student reasoning for various performance levels (low, medium, and high) of eighth-grade students, focusing on generating and interpreting algebraic representations. We argue this analysis allows a more comprehensive and complex perspective of student understanding. Our findings lay groundwork to investigate the continuum of algebraic understanding, and may help educators identify specific areas of students’ strength and weakness when solving cognitively demanding tasks. 相似文献
200.