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   26901篇
  免费   3141篇
  国内免费   3513篇
化学   9913篇
晶体学   105篇
力学   2640篇
综合类   208篇
数学   9281篇
物理学   11408篇
  2024年   83篇
  2023年   271篇
  2022年   592篇
  2021年   641篇
  2020年   823篇
  2019年   768篇
  2018年   767篇
  2017年   845篇
  2016年   1000篇
  2015年   884篇
  2014年   1341篇
  2013年   2179篇
  2012年   1413篇
  2011年   1694篇
  2010年   1356篇
  2009年   1726篇
  2008年   1770篇
  2007年   1859篇
  2006年   1519篇
  2005年   1310篇
  2004年   1099篇
  2003年   1120篇
  2002年   1028篇
  2001年   827篇
  2000年   829篇
  1999年   707篇
  1998年   639篇
  1997年   514篇
  1996年   354篇
  1995年   350篇
  1994年   268篇
  1993年   270篇
  1992年   281篇
  1991年   232篇
  1990年   220篇
  1989年   203篇
  1988年   178篇
  1987年   179篇
  1986年   152篇
  1985年   156篇
  1984年   149篇
  1983年   82篇
  1982年   115篇
  1981年   110篇
  1980年   94篇
  1979年   104篇
  1978年   81篇
  1977年   80篇
  1976年   72篇
  1973年   61篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
In this paper, we present some counterexamples which show that there is no theory on the spectrum of homogeneous compact operators which parallels the Riesz-Schauder theory on the spectrum of linear compact operators. These counterexamples also illustrate that it is impossible to study in a unified setting the Fucik spectrum of the Laplacian: -△w = au+ - bu- inΩand u = 0 on (?)Ω, as well as the spectrum of the p-Laplacian: -div(|(?)u| p-2(?)u) = λ|u|p-2u and u = 0 on (?)Ω.  相似文献   
82.
83.
The paper aims to obtain existence and uniqueness of the solution as well as asymptotic estimate of the solution for singularly perturbed nonlinear third- order Robin boundary value problem with a turning point.In order to achieve this aim,existence and uniqueness of the solution for third-order nonlinear Robin boundary value problem is derived first based on the upper and lower solutions method under relatively weaker conditions.In this manner,the goal of this paper is gained by applying the existence and uniqueness results mentioned above.  相似文献   
84.
In this paper, we study the nonlinear evolution equation of Hele-Shaw type with dynamical boundary conditions. That is, the equation utw+f where uH(w) and H is the Heaviside function, with boundary condition μ(x,w)tw+kwν=g, where ν denotes the outward normal vector of the fixed boundary of the domain. We prove existence, uniqueness and some qualitative properties of the solution.  相似文献   
85.
In this paper, variational conclusions of set-valued bifunctions on convex subsets of Banach spaces are investigated and several new results are obtained. The results are applied to the fixed point theory and variational inequalities. We obtain two fixed point theorems and existence theorems of solutions of variational inequalities.  相似文献   
86.
Optimal stopping problems by two or more decision makers: a survey   总被引:1,自引:0,他引:1  
A review of the optimal stopping problem with more than a single decision maker (DM) is presented in this paper. We classify the existing literature according to the arrival of the offers, the utility of the DMs, the length of the sequence of offers, the nature of the game and the number of offers to be selected. We enumerate various definitions for this problem and describe some dynamic approaches. Fouad Ben Abdelaziz is on leave from the Institut Superieur de Gestion, University of Tunis, Tunisia e-mail: foued.benabdelaz@isg.run.tn.  相似文献   
87.
In this paper, by using the fixed point theory, under quite general conditions on the nonlinear term, we obtain an existence result of bounded positive solutions of Schrödinger equations in two-dimensional exterior domains.  相似文献   
88.
From the standpoint of thermodynamic averaging of fission microprocesses, we investigate the origin of radioactive release in an NPP after an accident or after resource depletion. The genesis of the NPP release is interpreted as a new thermodynamic phenomenon, a zeroth-order phase transition. This problem setting results in a problem in probabilistic number theory. We prove the corresponding theorem leading to quantization of the Zipf law for the frequency of a zeroth-order phase transition with different values of the jump of the Gibbs thermodynamic potential. We introduce the notion of hole dimension. __________ Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 150, No. 1, pp. 118–142, January, 2007.  相似文献   
89.
We present a framework for efficiently performing Monte Carlo wave-function simulations in cavity QED with moving particles. It relies heavily on the object-oriented programming paradigm as realised in C++, and is extensible and applicable for simulating open interacting qua ntum dynamics in general. The user is provided with a number of “elements”, e.g. pumped moving particles, pumped lossy cavity modes, and various interactions to compose complex interacting systems, which contain several particles moving in electromagnetic fields of various configurations, and perform wave-function simulations on such systems. A number of tools are provided to facilitate the implementation of new elements.  相似文献   
90.
1846年,刘维尔在自己主办的杂志“纯粹与应用数学杂志”首次出版了伽罗瓦的数学研究,这对于伽罗瓦理论的传播与发展是具有决定意义的事件.伽罗瓦去世14年后,刘维尔发表伽罗瓦数学研究的原因是什么?采用数学历史文献分析法,得出四个重要原因:①伽罗瓦的朋友和弟弟的请求;②力图弥补科学院曾经造成的不公正;③刘维尔积极扶持年轻人的高贵品质使然;④刘维尔与利布里学术论战的促进.  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