首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   327篇
  免费   2篇
  国内免费   10篇
化学   6篇
力学   8篇
综合类   2篇
数学   288篇
物理学   35篇
  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.

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  
刘战存  卢文韬 《大学物理》2004,23(11):51-54,65
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 Int(A)={fB[X]|f(A)?A}, and the intersection of Int(A) with K[X] is IntK(A), which is a commutative subring of K[X]. The set Int(A) may or may not be a ring, but it always has the structure of a left IntK(A)-module.A D-algebra A which is free as a D-module and of finite rank is called IntK-decomposable if a D-module basis for A is also an IntK(A)-module basis for Int(A); in other words, if Int(A) can be generated by IntK(A) 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 IntK-decomposable so that it can be applied to D-algebras that are not necessarily free by defining A to be IntK-decomposable when Int(A) is isomorphic to IntK(A)?DA. 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 IntK-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 IntK-decomposable algebras correspond to unramified Galois extensions of K.  相似文献   
198.
We consider the max-cut and max-k-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 12-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.
MAX+PLUSⅡ在EDA中的应用   总被引:1,自引:0,他引:1  
介绍了MAX+PLUSⅡ软件在EDA中的应用,以正交解码/计数器的设计为例,说明了对Altera公司的FPGA进行图形设计、编译以及在系统编程(ISP)的方法和步骤。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号