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   143篇
  免费   14篇
  国内免费   21篇
化学   4篇
晶体学   2篇
力学   16篇
综合类   5篇
数学   121篇
物理学   30篇
  2022年   2篇
  2021年   3篇
  2020年   3篇
  2019年   3篇
  2018年   1篇
  2017年   6篇
  2016年   4篇
  2015年   7篇
  2014年   6篇
  2013年   9篇
  2012年   7篇
  2011年   8篇
  2010年   6篇
  2009年   13篇
  2008年   7篇
  2007年   11篇
  2006年   14篇
  2005年   9篇
  2004年   6篇
  2003年   14篇
  2002年   10篇
  2001年   4篇
  2000年   4篇
  1999年   5篇
  1997年   1篇
  1996年   1篇
  1995年   1篇
  1994年   1篇
  1993年   4篇
  1992年   2篇
  1991年   1篇
  1989年   1篇
  1987年   1篇
  1984年   1篇
  1980年   1篇
  1973年   1篇
排序方式: 共有178条查询结果,搜索用时 15 毫秒
41.
The main result of this paper is a new version of Newton-Hensel lifting that relates to interpolation questions. It allows one to lift polynomials in ℤ[x] from information modulo a prime number p ≠ 2 to a power pk for any k, and its originality is that it is a mixed version that not only lifts the coefficients of the polynomial but also its exponents. We show that this result corresponds exactly to a Newton--Hensel lifting of a system of 2t generalized equations in 2t unknowns in the ring of p-adic integers ℤp. Finally, we apply our results to sparse polynomial interpolation in ℤ[x].  相似文献   
42.
牛顿运动定律和机翼举力   总被引:2,自引:0,他引:2  
郭守月 《大学物理》2003,22(2):17-20
将空气简化为理想流体,由牛顿运动定律推出气体做曲线运动时的切向伯努利方程和法向压强梯度表达式,并解释了机翼举力。  相似文献   
43.
In an earlier paper (Mathematical Programming 43 (1989) 57–69) we characterized the class of facets of the set covering polytope defined by inequalities with coefficients equal to 0, 1 or 2. In this paper we connect that characterization to the theory of facet lifting. In particular, we introduce a family of lower dimensional polytopes and associated inequalities having only three nonzero coefficients, whose lifting yields all the valid inequalities in the above class, with the lifting coefficients given by closed form expressions.The research underlying this report was supported by Grant ECS-8601660 of the National Science Foundation, Contract N00014-85-K-0198 with the Office of Naval Research, and Grant AFOSR-870292 of the Air Force Office of Scientific Research.  相似文献   
44.
The basic order properties, as well as some metric and algebraic properties, are studied of the set of finitely additive transition functions on an arbitrary measurable space, as endowed with the structure of an ordered normed algebra, and some connections are revealed with the classical spaces of linear operators, vector measures, and measurable vector-valued functions. In particular, the question is examined of splitting the space of transition functions into the sum of the subspaces of countably additive and purely finitely additive transition functions.  相似文献   
45.
We introduce a projective approach for studying symmetric travelling salesman polytopes (STSPs). Thesymmetric travelling salesman polytope STSP(V) (resp.,Hamiltonian path polytope HP(V)) is the convex hull of incidence vectors of all Hamiltonian cycles (resp., paths) on the complete undirected graph with node setV. For any nodeh V, HP(V) is aprojection of STSP(V {h}). We show that HP(V) and STSP(V {h}) are isomorphic, and HP(V) is of full dimension minus one. By this projective approach, we obtain generalclique-lifting results, all based on simple conditions, for deriving large new classes of STSP facets. These results apply to all known non-trivial STSP facets, and generalize clique-lifting results of Maurras (1975), Grötschel and Padberg (1979) and Naddef and Rinaldi (1988).This research is supported in part by a grant from the Natural Sciences and Engineering Research Council of Canada to the first author.  相似文献   
46.
The concept of formal duality was proposed by Cohn, Kumar and Schürmann, which reflects a remarkable symmetry among energy‐minimizing periodic configurations. This formal duality was later translated into a purely combinatorial property by Cohn, Kumar, Reiher and Schürmann, where the corresponding combinatorial objects were called formally dual pairs. Motivated by this surprising application on the energy minimization problem, we focus on the algebraic constructions of primitive formally dual pairs. It is worth noting that almost all known examples of primitive formally dual pairs satisfy that the two subsets have the same size. Indeed, prior to this work, there was only one known example derived from computer search, which had subsets with unequal sizes in Z 2 × Z 4 2 . Inspired by this example, we propose a lifting construction framework and a recursive construction framework, which generate new primitive formally dual pairs from known ones. As an application, for m 2 , we obtain m + 1 pairwise inequivalent primitive formally dual pairs in Z 2 × Z 4 2 m , which have subsets with unequal sizes.  相似文献   
47.
48.
The lifting scheme has been found to be a flexible method for constructing scalar wavelets with desirable properties. Here it is extended to the construction of multiwavelets. It is shown that any set of compactly supported biorthogonal multiwavelets can be obtained from the Lazy matrix filters with a finite number of lifting steps. As an illustration of the general theory, compactly supported biorthogonal multiwavelets with optimum time–frequency resolution are constructed. In addition, experimental results of applying these multiwavelets to image compression are presented.  相似文献   
49.
The cuspidalization conjecture, which is a consequence of Grothendieck's section conjecture, asserts that for any smooth hyperbolic curve X over a finitely generated field k of characteristic 0 and any non empty Zariski open , every section of lifts to a section of . We consider in this article the problem of lifting Galois sections to the intermediate quotient introduced by Mochizuki 10 . We show that when and is an union of torsion sub‐packets every Galois section actually lifts to . One of the main tools in the proof is the construction of torus torsors and over X and the geometric interpretation .  相似文献   
50.
A compact C0 discontinuous Galerkin (CCDG) method is developed for solving the Kirchhoff plate bending problems. Based on the CDG (LCDG) method for Kirchhoff plate bending problems, the CCDG method is obtained by canceling the term of global lifting operator and enhancing the term of local lifting operator. The resulted CCDG method possesses the compact stencil, that is only the degrees of freedom belonging to neighboring elements are connected. The advantages of CCDG method are: (1) CCDG method just requires C0 finite element spaces; (2) the stiffness matrix is sparser than CDG (LCDG) method; and (3) it does not contain any parameter which can not be quantified a priori compared to C0 interior penalty (IP) method. The optimal order error estimates in certain broken energy norm and H1‐norm for the CCDG method are derived under minimal regularity assumptions on the exact solution with the help of some local lower bound estimates of a posteriori error analysis. Some numerical results are included to verify the theoretical convergence orders. © 2014 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 31: 1265–1287, 2015  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