全文获取类型
收费全文 | 1975篇 |
免费 | 155篇 |
国内免费 | 135篇 |
专业分类
化学 | 140篇 |
晶体学 | 7篇 |
力学 | 99篇 |
综合类 | 30篇 |
数学 | 1724篇 |
物理学 | 265篇 |
出版年
2024年 | 3篇 |
2023年 | 16篇 |
2022年 | 19篇 |
2021年 | 27篇 |
2020年 | 54篇 |
2019年 | 59篇 |
2018年 | 57篇 |
2017年 | 52篇 |
2016年 | 48篇 |
2015年 | 34篇 |
2014年 | 76篇 |
2013年 | 170篇 |
2012年 | 71篇 |
2011年 | 91篇 |
2010年 | 72篇 |
2009年 | 100篇 |
2008年 | 205篇 |
2007年 | 167篇 |
2006年 | 117篇 |
2005年 | 102篇 |
2004年 | 93篇 |
2003年 | 86篇 |
2002年 | 69篇 |
2001年 | 75篇 |
2000年 | 59篇 |
1999年 | 40篇 |
1998年 | 38篇 |
1997年 | 43篇 |
1996年 | 32篇 |
1995年 | 22篇 |
1994年 | 18篇 |
1993年 | 17篇 |
1992年 | 9篇 |
1991年 | 10篇 |
1990年 | 12篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 11篇 |
1986年 | 11篇 |
1985年 | 6篇 |
1984年 | 13篇 |
1983年 | 10篇 |
1982年 | 5篇 |
1981年 | 10篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1978年 | 9篇 |
1977年 | 10篇 |
1972年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有2265条查询结果,搜索用时 250 毫秒
111.
Poisson跳的拟线性倒向随机微分方程x(t) ∫tf(s,x(s),,x(s)) y(s)]dMs =ξ,t∈[0,1],这里M = (W,Q)T,其中W为Wiener过程,Q为补偿Poisson过程.利用区间延拓和 Bihari 不等式证明了在某种弱于Lipschitz条件下方程存在唯一适应解,并给出了解的估计,从而将文章[1]的结论推广到带 Poission 跳的情形.另外,本文还讨论了以下形式的边值问题:dx(t) = f(t,x(t),y(t))dt y(t)dMt,Ax(0) Bx(1) =ξ*,t∈[0,1],并证明了在Lipschitz条件下适应解的存在唯一性. 相似文献
112.
113.
H. Böhm J. Freyer M. Claassen W. Harth T. Bauer 《International Journal of Infrared and Millimeter Waves》1998,19(4):587-593
Investigations of GaAs-IMPATT diodes as self-pumped frequency doublers are carried out both, theoretically and experimentally. Optimization criterions are specified and first experimental results are presented. 1 mW output power has been achieved in the harmonic mode at 210 GHz. 相似文献
114.
H. Shigematsu 《Journal of statistical physics》1993,71(5-6):981-1002
Fluctuation of the average spin for one-dimensional Ising spins with nearest neighbor interactions are studied. The distribution function for the average spin is calculated for a finite volume, finite temperature, and finite magnetic field. As the volume increases and the temperature diminishes at zero magnetic field, there are two limits in which the probability distribution shows quite different behaviors: in the thermodynamic limit as the volume goes to infinity for finite temperature, small deviations of the fluctuations are described by a Gaussian distribution, and in the limit as the temperature vanishes for a finite volume, the ground states are realized with probability one. The crossover between these limits is analyzed via a ratio of the correlation length to the volume. The helix-coil transition in a polypeptide is discussed as an application. 相似文献
115.
116.
We prove the global Markov property for lattice systems of classical statistical mechanics, with bounded spins and finite range interactions. The method uses the one developed by two of us to prove the global Markov property of Euclidean generalized random fields. The result shows that the systems considered have a transition matrix, which together with a distribution on a hyperplane, describes completely the system. 相似文献
117.
118.
119.
It is shown how, among a class of generalized entropies, the Tsallis entropy can uniquely be identified by the principles of thermodynamics, the concept of stability, and the axiomatic foundations.Received: 6 May 2003, Accepted: 7 July 2003, Published online: 9 December 2003PACS:
05.20.-y, 05.70.-a, 05.90. + m, 65.40.Gr 相似文献
120.
Ilya?KuselmanEmail author Alexander?Weisman Wolfhard?Wegscheider 《Accreditation and quality assurance》2003,8(11):530-531
The current situation in the pharmaceutical industry is discussed, when the traceability of measurement (analytical) results to certified values of pharmacopoeial reference standards is required, without evaluating their uncertainties. It is shown that the evaluation of measurement uncertainty is necessary for understanding the level of confidence of the analytical results and their comparability, particularly during preparation and characterisation of the reference standards.Papers published in this section do not necessarily reflect the opinion of the Editors, the Editorial Board and the Publisher. Apart from exceptional circumstances, they are not submitted to the usual referee procedure and go essentially unaltered. 相似文献