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   9792篇
  免费   935篇
  国内免费   847篇
化学   1507篇
晶体学   46篇
力学   1114篇
综合类   241篇
数学   5785篇
物理学   2881篇
  2024年   13篇
  2023年   117篇
  2022年   188篇
  2021年   231篇
  2020年   287篇
  2019年   265篇
  2018年   267篇
  2017年   342篇
  2016年   364篇
  2015年   254篇
  2014年   462篇
  2013年   712篇
  2012年   442篇
  2011年   570篇
  2010年   493篇
  2009年   696篇
  2008年   678篇
  2007年   659篇
  2006年   613篇
  2005年   551篇
  2004年   419篇
  2003年   392篇
  2002年   355篇
  2001年   280篇
  2000年   291篇
  1999年   264篇
  1998年   274篇
  1997年   197篇
  1996年   158篇
  1995年   96篇
  1994年   101篇
  1993年   75篇
  1992年   64篇
  1991年   67篇
  1990年   48篇
  1989年   36篇
  1988年   43篇
  1987年   28篇
  1986年   33篇
  1985年   28篇
  1984年   23篇
  1983年   7篇
  1982年   20篇
  1981年   14篇
  1980年   11篇
  1979年   11篇
  1978年   10篇
  1977年   4篇
  1974年   3篇
  1972年   4篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
The knowledge of hydrocarbon/water phase equilibria is important in the design and operation of equipment for petroleum transport and refining and petrochemical plants. The presence of water in a hydrocarbon mixture can affect the product quality and damage the operation equipment due to corrosion and formation of gas hydrates. Tracing the concentration of hydrocarbons in aqueous media is also important for technical purposes like preventing oil spills and for ecological concerns such as predicting the fate of these organic pollutants in the environment.  相似文献   
52.
In this paper, we first define a kind of pseudo–distance function and annulus domain on Riemann surfaces, then prove the Hadamard Theorem and the Borel–Carathéodory Theorem on any Riemann surfaces. Supported by NSFC 10501052  相似文献   
53.
To validate approximate optimization schemes for estimate calculation algorithms (ECAs), it is necessary to compute the optimal height, which cannot be done in a reasonable amount of time. A variety of samples are built for which the optimal height of the ECAs is known by construction.  相似文献   
54.
In this note, we study convergence rates in the law of large numbers for independent and identically distributed random variables under sublinear expectations. We obtain a strong L^p-convergence version and a strongly quasi sure convergence version of the law of large numbers.  相似文献   
55.
In this paper, for the the primes p such that 3 is a divisor of p − 1, we prove a result which reduces the computation of the linear complexity of a sequence over GF(p m) (any positive integer m) with the period 3n (n and p m − 1 are coprime) to the computation of the linear complexities of three sequences with the period n. Combined with some known algorithms such as generalized Games-Chan algorithm, Berlekamp-Massey algorithm and Xiao-Wei-Lam-Imamura algorithm, we can determine the linear complexity of any sequence over GF(p m) with the period 3n (n and p m − 1 are coprime) more efficiently.  相似文献   
56.
 Let kn be positive integers. A finite, simple, undirected graph is called k-critically n-connected, or, briefly, an (n,k)-graph, if it is noncomplete and n-connected and the removal of any set X of at most k vertices results in a graph which is not (n−|X|+1)-connected. We present some new results on the number of vertices of an (n,k)-graph, depending on new estimations of the transversal number of a uniform hypergraph with a large independent edge set. Received: April 14, 2000 Final version received: May 8, 2001  相似文献   
57.
The implementation of a nonzero-order joint transform correlator using the double port Mach-Zehnder interferometric technique is proposed and demonstrated. This approach provides on-line processing for directly removing the zero-order components of a joint power spectrum in one step and performs the nonzero-order optical correlation. Experimental results are presented and discussed.  相似文献   
58.
This paper proposes the Rice condition numbers for invariant subspace, singular sub-spaces of a matrix and deflating subspaces of a regular matrix pair. The first-order perturbation estimations for these subspaces are derived by applying perturbation expansions of orthogonal projection operators.  相似文献   
59.
In this paper, we give new lower bounds for the size of Δ-critical graphs with Δ=8,9 which improve the partial results of Luo [6] and Y. Zhao [12].  相似文献   
60.
连通图的离散度是用s(G)来表示的,s(G)=max{ω(G-S)-|S|:ω(G-S)>1,SV(G)}.给出了两个完全图乘积的和一个完全图与路的乘积的离散度.还给出了两个完全图乘积的坚韧度.  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