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   788篇
  免费   122篇
  国内免费   42篇
化学   29篇
晶体学   2篇
力学   46篇
综合类   7篇
数学   403篇
物理学   465篇
  2023年   5篇
  2022年   6篇
  2021年   15篇
  2020年   13篇
  2019年   12篇
  2018年   14篇
  2017年   11篇
  2016年   15篇
  2015年   9篇
  2014年   38篇
  2013年   51篇
  2012年   24篇
  2011年   41篇
  2010年   50篇
  2009年   48篇
  2008年   56篇
  2007年   38篇
  2006年   48篇
  2005年   46篇
  2004年   41篇
  2003年   49篇
  2002年   40篇
  2001年   21篇
  2000年   23篇
  1999年   22篇
  1998年   28篇
  1997年   19篇
  1996年   14篇
  1995年   14篇
  1994年   12篇
  1993年   8篇
  1992年   12篇
  1991年   9篇
  1990年   10篇
  1989年   8篇
  1988年   7篇
  1987年   8篇
  1986年   4篇
  1985年   11篇
  1984年   12篇
  1983年   3篇
  1982年   8篇
  1981年   5篇
  1980年   5篇
  1979年   4篇
  1978年   4篇
  1977年   2篇
  1976年   2篇
  1974年   2篇
  1973年   3篇
排序方式: 共有952条查询结果,搜索用时 109 毫秒
91.
92.
证明了紧承下方图度量不是平移不变的.对紧承下方图度量的代数运算的连续性进行了讨论.证明了关于紧承下方图度量,模糊数空间只能是嵌入到拓扑向量空间当中,但不嵌入赋范线性空间当中.并与关于上确界度量的结果进行了比较.最后,给出了一个紧承下方图度量的下界.  相似文献   
93.
In this paper, we undertake a revision and a generalization of the results contained in the only paper so far published on the matter of translation invariance by allowing inputs and outputs to take not only zero but negative values. This broadens the field of application of the DEA methodology.  相似文献   
94.
In this paper we relate the group of automorphisms of a principal fibre bundle with the (second) Bianchi identity generalizing a result of Kazdan.During the preparation of this paper the author was supported by a fellowship of theGraduiertenkolleg Geometrie und Mathematische Physik at the Ruhr-Universität Bochum.  相似文献   
95.
The scale invariance technique has been employed to discuss theη i-driven turbulent transport under a new fluid model developed by Kimet al [1]. Our analysis reveals that the finite Larmour radius effect plays a decisive role to determine the scaling behaviour of the energy transport under the new fluid model. However, the overall scaling of the transport coefficient remains unchanged as compared to that derived by Connor [2] under the traditional fluid model. The approximations considered by Connor [2] are qualified with additional requirements within the new fluid approach. In the dissipative case, which has not been discussed earlier, additional constraints on the power scaling laws of the transport properties are imposed due to the dissipative mechanisms in the basic governing equations.  相似文献   
96.
In this paper, we extend the Hölderian invariance principle of Lamperti [6] to the case of partial-sum processes based on a triangular array of row-wise independent random variables. As an application, we obtain necessary and sufficient conditions for the almost sure (resp. in probability) weak Hölder convergence of partial-sum processes based on bootstrapped samples.  相似文献   
97.
This article deals with empty spacetime and the question of its physical reality. By “empty spacetime” we mean a collection of bare spacetime points, the remains of ridding spacetime of all matter and fields. We ask whether these geometric objects—themselves intrinsic to the concept of field—might be observable through some physical test. By taking quantum-mechanical notions into account, we challenge the negative conclusion drawn from the diffeomorphism invariance postulate of general relativity, and we propose new foundational ideas regarding the possible observation—as well as conceptual overthrow—of this geometric ether.  相似文献   
98.
We obtain estimates for the distributions of errors which arise in approximation of a random polygonal line by a Wiener process on the same probability space. The polygonal line is constructed on the whole axis for sums of independent nonidentically distributed random variables and the distance between it and the Wiener process is taken to be the uniform distance with an increasing weight. All estimates depend explicitly on truncated power moments of the random variables which is an advantage over the earlier estimates of Komlos, Major, and Tusnady where this dependence was implicit.  相似文献   
99.
100.
A simple two ordinary lens system is proposed to realize the fractional Fourier transform (FRT) of continuously variable order while keeping the scaling factors of both the input and output functions as the same constant independent of the geometric parameters of the system and the FRT orders. It can remove the necessity and inconvenience of using input masks of different scales or any other special devices, and then is helpful to those who want to observe the FRT but have no specific facilities.  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