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   52467篇
  免费   1677篇
  国内免费   14篇
化学   30710篇
晶体学   296篇
力学   909篇
综合类   1篇
数学   10353篇
物理学   11889篇
  2023年   359篇
  2022年   324篇
  2021年   530篇
  2020年   740篇
  2019年   699篇
  2018年   1099篇
  2017年   1027篇
  2016年   1910篇
  2015年   1583篇
  2014年   1595篇
  2013年   3470篇
  2012年   3177篇
  2011年   3063篇
  2010年   2026篇
  2009年   1720篇
  2008年   2597篇
  2007年   2381篇
  2006年   2075篇
  2005年   2057篇
  2004年   1804篇
  2003年   1519篇
  2002年   1333篇
  2001年   1046篇
  2000年   1061篇
  1999年   769篇
  1998年   612篇
  1997年   535篇
  1996年   647篇
  1995年   470篇
  1994年   543篇
  1993年   503篇
  1992年   531篇
  1991年   442篇
  1990年   499篇
  1989年   405篇
  1988年   418篇
  1987年   367篇
  1986年   371篇
  1985年   507篇
  1984年   495篇
  1983年   373篇
  1982年   395篇
  1981年   406篇
  1980年   326篇
  1979年   336篇
  1978年   331篇
  1976年   347篇
  1975年   311篇
  1974年   318篇
  1973年   309篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
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   
132.
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   
133.
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   
134.
In the present paper, Daubechies' wavelets and the computation of their scaling coefficients are briefly reviewed. Then a new method of computation is proposed. This method is based on the work [7] concerning a new orthonormality condition and relations among scaling moments, respectively. For filter lengths up to 16, the arising system can be explicitly solved with algebraic methods like Gröbner bases. Its simple structure allows one to find quickly all possible solutions.  相似文献   
135.
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   
136.
The composition and the permeation properties of the skin are dependent on age. In the animal models for permation studies, age affects the mechanical as well as the permeation properties significantly. The time dependence of permeation of 147Pm3+ from aqueous solution was established by the animal skin model and the age dependence of promethium permeation through the skin was examined. The aim was to find the optimum rat skin age model for radionuclide permeation studies and to assess the relative importance of the main permeation pathways: transepidermal and transfollicular permeation. The skin from 5-day-old rats (5DR) was found to represent the optimum animal model to study transepidermal permeation of ions. The skin from 9-day-old rats (9DR) was selected to study transfollicular permeation of ions. Comparison of the permeated amounts of promethium through the skin without hairs (3 DR to 6 DR) and with hairs (7DR to 12DR) showed that the additional permation mode via follicles significantly contributed to the permeation rate and extent.  相似文献   
137.
138.
In this work we introduce a class of balanced numerical schemes, up to second order, for the solution of general non-homogeneous hyperbolic systems of conservation laws. We give a general technique to build such schemes. We also prove that they balance up to second order a large class of steady solutions in the whole domain but some subset whose measure tends to zero as the grid size decreases to zero. We finally present an application to Shallow Water equations that exhibit the good performances of some of the schemes introduced. To cite this article: T. Chacón Rebollo et al., C. R. Acad. Sci. Paris, Ser. I 338 (2004).  相似文献   
139.
In bricklayers' model, which is a generalization of the misanthrope processes, we show that a nontrivial class of product distributions is closed under the time-evolution of the process. This class also includes measures fitting to shock data of the limiting PDE. In particular, we show that shocks of this type with discontinuity of size one perform ordinary nearest neighbor random walks only interacting, in an attractive way, via their jump rates. Our results are related to those of Belitsky and Schütz(4) on the simple exclusion process, although we do not use quantum formalism as they do. The structures we find are described from a fixed position. Similar ones were found in Balázs,(2) valak as seen from the random position of the second class particle.  相似文献   
140.
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