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   3192篇
  免费   145篇
  国内免费   261篇
化学   856篇
力学   80篇
综合类   17篇
数学   2117篇
物理学   528篇
  2024年   9篇
  2023年   40篇
  2022年   50篇
  2021年   89篇
  2020年   89篇
  2019年   108篇
  2018年   92篇
  2017年   111篇
  2016年   114篇
  2015年   98篇
  2014年   174篇
  2013年   309篇
  2012年   167篇
  2011年   156篇
  2010年   135篇
  2009年   227篇
  2008年   225篇
  2007年   233篇
  2006年   171篇
  2005年   129篇
  2004年   108篇
  2003年   104篇
  2002年   89篇
  2001年   62篇
  2000年   67篇
  1999年   72篇
  1998年   55篇
  1997年   60篇
  1996年   44篇
  1995年   41篇
  1994年   26篇
  1993年   20篇
  1992年   25篇
  1991年   13篇
  1990年   9篇
  1989年   10篇
  1988年   5篇
  1987年   4篇
  1986年   2篇
  1985年   9篇
  1984年   10篇
  1983年   7篇
  1982年   9篇
  1981年   7篇
  1980年   3篇
  1979年   4篇
  1978年   4篇
  1977年   2篇
  1976年   1篇
排序方式: 共有3598条查询结果,搜索用时 0 毫秒
91.
It is shown that any elloptic or parabolic operator in nondivergence form with measurable coefficients has a global fundamental solution verifying certain pointwise bounds.  相似文献   
92.
We construct a quantum circuit to produce a task-oriented partially entangled state and use it as the quantum channel for controlled joint remote state preparation. Unlike most previous works, where the parameters of the quantum channel are given to the receiver who can accomplish the task only probabilistically by consuming auxiliary resource, operation and measurement, here we give them to the supervisor. Thanks to the knowledge of the task-oriented quantum channel parameters, the supervisor can carry out proper complete projective measurement, which, combined with the feed-forward technique adapted by the preparers, not only much economizes (simplifies) the receiver's resource (operation) but also yields unit total success probability. Notably, such apparent perfection does not depend on the entanglement degree of the shared quantum channel. Our protocol is within the reach of current quantum technologies.  相似文献   
93.
The problem of the presence of Cantor part in the derivative of a solution to a hyperbolic system of conservation laws is considered.An overview of the techniques involved in the proof is given,and a c...  相似文献   
94.
In this paper, a simultaneous canonical form of a pair of rectangular complex matrices is developed. Using this new tool we give a necessary and sufficient condition to assure that the reverse order law is valid for the weighted Moore–Penrose inverse. Additionally, we characterize matrices ordered by the weighted star partial order and adjacent matrices as applications.  相似文献   
95.
《Analytical letters》2012,45(11):2051-2058
Abstract

The use of partial least-squares spectrophotometric calibration for the simultaneous determination of suppositories in a multicomponent formulation is presented. This method is applied to the deternination of acetaminophen and phenobarbital in suppository preparations. The results show that these components in a molar ratio of about 61:1 in suppositories have been determined simultaneously with high precision.  相似文献   
96.
In this paper, we present some results relating different matrix partial orderings and the invertibility of a linear combination of EP matrices.  相似文献   
97.
This paper is a consequence for a paper of Lin et al. [S.W. Lin, Y.W. Wou, P. Julian, Note on minimax distribution free procedure for integrated inventory model with defective goods and stochastic lead time demand, Appl. Math. Model. 35 (2011) 2087–2093]. We simplified their complicated solution procedure and then presented a revision to patch their negligence for the boundary minimums. Numerical examples are provided to demonstrate our findings.  相似文献   
98.
The equations for a self-similar solution to an inviscid incompressible fluid are mapped into an integral equation that hopefully can be solved by iteration. It is argued that the exponents of the similarity are ruled by Kelvin's theorem of conservation of circulation. The end result is an iteration with a nonlinear term entering a kernel given by a 3D integral for a swirling flow, likely within reach of present-day computational power. Because of the slow decay of the similarity solution at large distances, its kinetic energy diverges, and some mathematical results excluding non-trivial solutions of the Euler equations in the self-similar case do not apply.  相似文献   
99.
100.
Nursel Erey 《代数通讯》2018,46(9):4007-4020
We show that if G is a gap-free and diamond-free graph, then I(G)s has a linear minimal free resolution for every s≥2.  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