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   395181篇
  免费   3067篇
  国内免费   1251篇
化学   178438篇
晶体学   5468篇
力学   21501篇
综合类   2篇
数学   76249篇
物理学   117841篇
  2020年   1795篇
  2019年   2072篇
  2018年   18885篇
  2017年   19434篇
  2016年   12383篇
  2015年   4104篇
  2014年   4289篇
  2013年   11596篇
  2012年   14897篇
  2011年   29500篇
  2010年   17584篇
  2009年   17925篇
  2008年   23936篇
  2007年   28922篇
  2006年   8758篇
  2005年   15537篇
  2004年   11559篇
  2003年   11055篇
  2002年   8310篇
  2001年   7555篇
  2000年   5886篇
  1999年   4366篇
  1998年   3744篇
  1997年   3706篇
  1996年   3580篇
  1995年   3319篇
  1994年   3091篇
  1993年   3149篇
  1992年   3406篇
  1991年   3455篇
  1990年   3253篇
  1989年   3218篇
  1988年   3293篇
  1987年   3158篇
  1986年   3046篇
  1985年   4108篇
  1984年   4277篇
  1983年   3519篇
  1982年   3864篇
  1981年   3754篇
  1980年   3636篇
  1979年   3681篇
  1978年   3916篇
  1977年   3649篇
  1976年   3874篇
  1975年   3446篇
  1974年   3564篇
  1973年   3914篇
  1972年   2378篇
  1971年   1816篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
On a sequence of embedded nonuniform grids, chains of embedded spaces of minimal splines (not necessarily polynomial) are constructed. The wavelet decomposition is given. The basis wavelets are compactly supported and admit simple analytic representation. The corresponding decomposition and reconstruction formulas are derived. The variety of spaces under consideration is identified with the variety of complete sequences of points of the direct product of an interval and a projective plane. Bibliography: 20 titles. __________ Translated from Problemy Matematicheskogo Analiza, No. 35, 2007, pp. 15–31  相似文献   
992.
993.
A base of the universal multiplicative envelope of the free Malcev superalgebra ℳ on one odd generator is constructed. Some corollaries for skew-symmetric functions and central elements in free Malcev and free alternative algebras are obtained. Moreover, a base of the Poisson-Malcev superalgebra of ℳ is constructed. As a corollary, a set of elements that spans the free alternative superalgebra on one odd generator is obtained. __________ Translated from Fundamentalnaya i Prikladnaya Matematika, Vol. 10, No. 4, pp. 97–106, 2004.  相似文献   
994.
In this paper,we provide a new class of up-embeddable graphs,and obtain a tight lower bound on the maximum genus of a class of 2-connected pseudographs of diameter 2 and of a class of diameter 4 multi-graphs.This extends a result of Skoviera.  相似文献   
995.
The goal of this paper is to generalize a theorem of Fujiwara (Deligne’s conjecture) to the situation appearing in a joint work [KV] with David Kazhdan on the global Langlands correspondence over function fields. Moreover, our proof is more elementary than the original one and stays in the realm of ordinary algebraic geometry, that is, does not use rigid geometry. We also give a proof of the Lefschetz–Verdier trace formula and of the additivity of filtered trace maps, thus making the paper essentially self-contained. The work was supported by the Israel Science Foundation (Grant No. 555/04) Received: May 2005 Accepted: August 2005  相似文献   
996.
997.
It is demonstrated theoretically that the initial (both elastic and viscous) magnetic susceptibility components for nanocrystalline magnets caused by the processes of rotations (in the region of linear response) have resonant rather than relaxation character typical already for the susceptibility component caused by displacements of domain boundaries. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 88–92, June, 2007.  相似文献   
998.
Let X be a smooth projective variety of dimension 2k-1 (k≥3) over the complex number field. Assume that fR: X→Y is a small contraction such that every irreducible component Ei of the exceptional locus of fR is a smooth subvariety of dimension k. It is shown that each Ei is isomorphic to the k-dimensional projective space Pk, the k-dimensional hyperquadric surface Qk in Pk 1, or a linear Pk-1-bundle over a smooth curve.  相似文献   
999.
1000.
We propose an alternative method for computing effectively the solution of non-linear, fixed-terminal-time, optimal control problems when they are given in Lagrange, Bolza or Mayer forms. This method works well when the nonlinearities in the control variable can be expressed as polynomials. The essential of this proposal is the transformation of a non-linear, non-convex optimal control problem into an equivalent optimal control problem with linear and convex structure. The method is based on global optimization of polynomials by the method of moments. With this method we can determine either the existence or lacking of minimizers. In addition, we can calculate generalized solutions when the original problem lacks of minimizers. We also present the numerical schemes to solve several examples arising in science and technology.  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