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   13085篇
  免费   359篇
  国内免费   2篇
化学   6700篇
晶体学   86篇
力学   300篇
数学   3002篇
物理学   3358篇
  2021年   103篇
  2020年   150篇
  2019年   145篇
  2018年   260篇
  2017年   253篇
  2016年   485篇
  2015年   403篇
  2014年   472篇
  2013年   978篇
  2012年   613篇
  2011年   812篇
  2010年   473篇
  2009年   406篇
  2008年   572篇
  2007年   530篇
  2006年   464篇
  2005年   289篇
  2004年   302篇
  2003年   250篇
  2002年   254篇
  2001年   194篇
  2000年   198篇
  1999年   160篇
  1998年   149篇
  1997年   137篇
  1996年   130篇
  1995年   119篇
  1994年   106篇
  1993年   113篇
  1992年   128篇
  1991年   107篇
  1990年   127篇
  1989年   109篇
  1988年   112篇
  1987年   107篇
  1986年   101篇
  1985年   151篇
  1984年   165篇
  1983年   128篇
  1982年   139篇
  1981年   131篇
  1980年   130篇
  1979年   139篇
  1978年   152篇
  1977年   115篇
  1976年   142篇
  1975年   129篇
  1974年   132篇
  1973年   105篇
  1972年   90篇
排序方式: 共有10000条查询结果,搜索用时 640 毫秒
31.
We study three problems of the light-front field theory quantized in a finite volume with fields (anti-)periodic in x: (a) microcausality by deriving an integral representation for the discrete Pauli-Jordan function; (b) surface terms violating Poincaré algebra; (c) a LF version of the Goldstone theorem. The first two problems are resolved by careful mathematical treatment. The third one illustrates the usefulness of DLCQ as an analytical scheme.  相似文献   
32.
Here we prove a limit theorem in the sense of the weak convergence of probability measures in the space of meromorphic functions for a general Dirichlet series. The explicit form of the limit measure in this theorem is given. Partially supported by Lithuanian Foundation of Studies and Science  相似文献   
33.
In this paper a new definition of a lattice valued intuitionistic fuzzy set (LIFS) is introduced, in an attempt to overcome the disadvantages of earlier definitions. Some properties of this kind of fuzzy sets and their basic operations are given. The theorem of synthesis is proved: For every two families of subsets of a set satisfying certain conditions, there is an lattice valued intuitionistic fuzzy set for which these are families of level sets. The research supported by Serbian Ministry of Science and Technology, Grant No. 1227.  相似文献   
34.
In the paper the asymptotics for Dirichlet polynomials associated to certain cusp forms are obtained. Partially supported by Lithuanian Foundation of Studies and Science  相似文献   
35.
We use a class of generalized relative entropies on density matrices to obtain one-parameter families of torsion-free affine connections.  相似文献   
36.
37.
38.
39.
Thermal decomposition of lanthanum nitrate to lanthanum oxide was carried out by both temperature programmed heating (TPH) and citrate-gel combustion. The temperature programmed heating was carried out under flow of oxidizing (air), neutral (nitrogen) and reducing (25 vol.% hydrogen+argone mixture) gases, and the processes were controlled by simultaneous thermogravimetry and differential thermal analysis. It was shown that hydrogen atmosphere helps to reduce temperatures of all decomposition steps. The results of TPH were utilized to check the nature of residues in the products of lanthanum nitrate-to-oxide conversion performed via citrate-gel combustion technique.  相似文献   
40.
Summary. We introduce linear semi-implicit complementary volume numerical scheme for solving level set like nonlinear degenerate diffusion equations arising in image processing and curve evolution problems. We study discretization of image selective smoothing equation of mean curvature flow type given by Alvarez, Lions and Morel ([3]). Solution of the level set equation of Osher and Sethian ([26], \[30]) is also included in the study. We prove and estimates for the proposed scheme and give existence of its (generalized) solution in every discrete time-scale step. Efficiency of the scheme is given by its linearity and stability. Preconditioned iterative solvers are used for computing arising linear systems. We present computational results related to image processing and plane curve evolution. Received April 25, 2000 / Revised version received June 11, 2001 / Published online November 15, 2001  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