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   115篇
  免费   8篇
  国内免费   27篇
化学   3篇
力学   7篇
综合类   2篇
数学   134篇
物理学   4篇
  2023年   1篇
  2022年   1篇
  2021年   1篇
  2020年   3篇
  2019年   4篇
  2018年   2篇
  2017年   3篇
  2016年   5篇
  2015年   2篇
  2014年   2篇
  2013年   6篇
  2012年   1篇
  2011年   4篇
  2010年   6篇
  2009年   6篇
  2008年   5篇
  2007年   7篇
  2006年   7篇
  2005年   5篇
  2004年   5篇
  2003年   9篇
  2002年   6篇
  2001年   3篇
  2000年   6篇
  1999年   7篇
  1998年   6篇
  1997年   7篇
  1996年   13篇
  1995年   3篇
  1994年   2篇
  1991年   1篇
  1989年   1篇
  1988年   1篇
  1985年   3篇
  1984年   2篇
  1983年   1篇
  1982年   2篇
  1980年   1篇
排序方式: 共有150条查询结果,搜索用时 0 毫秒
41.
This article reports the proton tautomerization effects of distal histidine residues in carbonmonoxy myoglobin according to the density functional calculations of the whole protein. The electron eigenstates and electrostatic potential (ESP) distributed around heme and its pocket vary significantly depending on the protonation positions of the distal histidine residues. To investigate the range over which the electronic structures are affected by the proton tautomerization, the quantum mechanics/molecular mechanics (QM/MM) method is applied to probe the QM size to reproduce the atomic partial charges and ESP around the active center. Consequently, we show that these properties converged for the 300 pm QM/MM system in this study. During the analysis, we also find that amino residues such as Phe43, Val68, and Phe138 interact strongly with heme through orbital mixing, indicating that the protein is a medium not only interacting with the reaction center, but also buffering on electrons. © 2013 Wiley Periodicals, Inc.  相似文献   
42.
A homeomorphism of Rn onto itself is called positively regular (or EC+) iff its family of non-negative iterates is pointwise equicontinuous. For EC+ homeomorphism of Rn such that some point of Rn has bounded positive semi-orbit, the nucleus M is defined, and the following theorems are proved.Theorem 1. If such a homeomorphism h:RnRn has compact nucleus M, then M is a fully invariant compact AR. Further, for n≠4,5,h:Rn/MRn/M is conjugate to a contraction on Rn.Theorem 2. In Rn,n≠4,5,M compact iff there existsa disk D such that h(D)?IntD.Theorem 3. In R2, either M is a disk and h|M is a rotation, or h|M is periodic. The relationship between M and the irregular set of ? is also studied.  相似文献   
43.
We establish relations between the notions of almost automorphic, Levitan almost periodic and regularly almost periodic points in compact minimal flows for the case of the acting groups whose all continuous characters have syndetic kernels. In particular, we generalize and give a new proof of a theorem by Bronstein.   相似文献   
44.
The purpose of this note is to give a short proof of the theorem of Ralph in Linear Algebra Appl. 178 (1993), 249–260, on the geometry of projection maps. This theorem implies that the so-called normal maps derived from projections satisfy a general geometric criterion for bijectivity of piecewise affine maps given by Kuhn and Löwen in Linear Algebra Appl. 96 (Section 5.3), (1987), 109–129. As a consequence, one obtains Robinson's characterization of bijectivity of normal maps.  相似文献   
45.
We define and investigateCD Σ,Γ(K, E)-type spaces, which generalizeCD 0-type Banach lattices introduced in [1]. We state that the space CD Σ,Γ(K, E) can be represented as the space of E-valued continuous functions on the generalized Alexandroff Duplicate of K. As a corollary we obtain the main result of [6, 8].  相似文献   
46.
In this paper linear hyperbolic cocycles are classified by the relation of topological conjugacy. Roughly speaking, two linear cocycles are conjugate if there exists a homeomorphism which maps their trajectories into each other. The problem of classification of discrete-time deterministic hyperbolic dynamical systems was investigated by Robbin (1972). He proved that there exist 4d classes ofd-dimensional deterministic discrete hyperbolic dynamical systems. We obtain a criterion for topological conjugacy of two linear hyperbolic cocycles and show that the number of classes depends crucially on the ergodic properties of the metric dynamical system over which they are defined. Our result is a generalization of the deterministic theorem of Robbin.  相似文献   
47.
漆毅 《数学进展》2003,32(1):35-38
本文指出了Ara Basmajian在美国数学会出版的“Contemporary Mathematics”第221卷中提出的一个关于Teichmuller空间的问题的答案是完全否定的。  相似文献   
48.
We prove that the set of all regular points of a flow of Brouwer homeomorphisms is invariant under topological equivalence of flows. We also show that a similar result holds for the first prolongational limit set.  相似文献   
49.
51.IntroductionLethbeahomeomorphismontherealaxisR,andsatisfyh(lco)=loo.Wecallaquasisymmetricfunction.lfthereexistsa'constantMsuchthatM-1Sp(x,t)SM,x,teR,(l.2)then(1.2)iscalledtheM-condition-Byvirtueoftheclassicresultofpaper[lj,ifp(x,t)sat-isfiestheM-condition,thenthereexistsaK(M')-quasiconformaIextensiononthel1alfplaneH,whichisthewell-knownBeurling-Ahlfors'extension:ytz)=u(x,y) iv(x,y),whereAfterpaper[lj,manyworkshavebeendoneforestimatingK-Particularly,itshouldbere-markedheretl1atM.Leht…  相似文献   
50.
The complementarity problem with a nonlinear continuous mappingf from the nonnegative orthantR + n ofR n intoR n can be written as the system of equationsF(x, y) = 0 and(x, y) R + 2n , whereF denotes the mapping from the nonnegative orthantR + 2n ofR 2n intoR + n × Rn defined byF(x, y) = (x 1y1,,xnyn, f1(x) – y1,, fn(x) – yn) for every(x, y) R + 2n . Under the assumption thatf is a uniformP-function, this paper establishes that the mappingF is a homeomorphism ofR + 2n ontoR + n × Rn. This result provides a theoretical basis for a new continuation method of tracing the solution curve of the one parameter family of systems of equationsF(x, y) = tF(x 0, y0) and(x, y) R + 2n from an arbitrary initial point(x 0, y0) R + 2n witht = 1 until the parametert attains 0. This approach is an extension of the one used in the polynomially bounded algorithm recently given by Kojima, Mizuno and Yoshise for solving linear complementarity problems with positive semi-definite matrices.  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