全文获取类型
收费全文 | 27926篇 |
免费 | 6378篇 |
国内免费 | 3685篇 |
专业分类
化学 | 13439篇 |
晶体学 | 331篇 |
力学 | 1796篇 |
综合类 | 252篇 |
数学 | 2128篇 |
物理学 | 20043篇 |
出版年
2024年 | 76篇 |
2023年 | 338篇 |
2022年 | 1001篇 |
2021年 | 1109篇 |
2020年 | 1094篇 |
2019年 | 949篇 |
2018年 | 888篇 |
2017年 | 1088篇 |
2016年 | 1344篇 |
2015年 | 1087篇 |
2014年 | 1579篇 |
2013年 | 2421篇 |
2012年 | 1794篇 |
2011年 | 1979篇 |
2010年 | 1634篇 |
2009年 | 1788篇 |
2008年 | 2015篇 |
2007年 | 1894篇 |
2006年 | 1860篇 |
2005年 | 1537篇 |
2004年 | 1418篇 |
2003年 | 1250篇 |
2002年 | 1141篇 |
2001年 | 949篇 |
2000年 | 941篇 |
1999年 | 664篇 |
1998年 | 712篇 |
1997年 | 534篇 |
1996年 | 438篇 |
1995年 | 390篇 |
1994年 | 330篇 |
1993年 | 279篇 |
1992年 | 251篇 |
1991年 | 184篇 |
1990年 | 171篇 |
1989年 | 148篇 |
1988年 | 139篇 |
1987年 | 96篇 |
1986年 | 86篇 |
1985年 | 70篇 |
1984年 | 73篇 |
1983年 | 27篇 |
1982年 | 48篇 |
1981年 | 34篇 |
1980年 | 19篇 |
1979年 | 20篇 |
1978年 | 31篇 |
1977年 | 13篇 |
1976年 | 12篇 |
1973年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 562 毫秒
51.
Piotr Garbaczewski 《Journal of statistical physics》2006,123(2):315-355
We analyze the functioning of Gibbs-type entropy functionals in the time domain, with emphasis on Shannon and Kullback-Leibler entropies of time-dependent continuous probability distributions. The Shannon entropy validity is extended to probability distributions inferred from L
2(R
n
) quantum wave packets. In contrast to the von Neumann entropy which simply vanishes on pure states, the differential entropy quantifies the degree of probability (de)localization and its time development. The associated dynamics of the Fisher information functional quantifies nontrivial power transfer processes in the mean, both in dissipative and quantum mechanical cases.
PACS NUMBERS: 05.45.+b, 02.50.-r, 03.65.Ta, 03.67.-a 相似文献
52.
HE Guang-Qiang ZENG Gui-Hua 《理论物理通讯》2006,46(1):61-64
A quantum encryption protocol based on Gaussian-modulated continuous variable EPR correlations is proposed. The security is guaranteed by continuous variable EPR entanglement correlations produced by nondegenerate optical parametric amplifier (NOPA). For general beam splitter eavesdropping strategy, the mutual information I(α, ε) between Alice and Eve is caJculated by employing Shannon information theory. Finally the security analysis is presented. 相似文献
54.
Homohelicity induction of a series of propylene-linked zinc bilinone (ZnBL; linear tetrapyrrople-zinc(II) complex) dimers upon complexation with chiral amine and α-amino esters was investigated. Introduction of substituents such as dimethyl and diisobutyl to the central carbon of the propylene spacer gave rise to stabilization of the homohelical (PP and MM) conformers rather than the heterohelical (PM) conformer. As bulkiness of the substituent increased, stability of the homohelical conformers was raised. The preorganization of the homohelical structures led to significantly amplified homohelicity induction upon complexation with chiral amine and α-amino esters. 相似文献
55.
多普勒效应测试仪的改进 总被引:3,自引:0,他引:3
为了解决电磁波多普勒效应在实验室演示的困难,采用单片机和一系列大规模集成电路设计了一种演示电磁波多普勒效应的测试仪器,分析了电磁波的多普勒效应原理,给出了该仪器的组成结构,介绍了该仪器铁特点。 相似文献
56.
Examples are worked out using a new equation proposed in the previous paper to show that it has new physical predictions for mesoscopic systems. 相似文献
57.
58.
X-ray diffraction patterns of nanocrystalline Fe-Cu-Nb-Si-B (FINEMET) alloys reveal that bcc α-Fe/α-FeSi crystallites with
the average grain size of 20(5) nm are dispersed in amorphous matrix. Enhanced electron—electron interaction (EEI) and quantum
interference (QI) effects as well as electron-magnon (and/or electron-spin fluctuation) scattering turn out to be the main
mechanisms that govern the temperature dependence of resistivity. Of all the inelastic scattering processes, inelastic electron-phonon
scattering is the most effective mechanism to destroy phase coherence of electron wave functions. The diffusion constant,
density of states at the Fermi level and the inelastic scattering time have been estimated, for the first time, for the alloys
in question
Article presented at the International Symposium on Advances in Superconductivity and Magnetism: Materials, Mechanisms and
Devices, ASMM2D-2001, 25–28 September 2001, Mangalore, India. 相似文献
59.
A. Khrennikov 《Annalen der Physik》2003,12(10):575-585
We study the probabilistic consequences of the choice of the basic number field in the quantum formalism. We demonstrate that by choosing a number field for a linear space representation of quantum model it is possible to describe various interference phenomena. We analyse interference of probabilistic alternatives induced by real, complex, hyperbolic (Clifford) and p‐adic representations. 相似文献
60.