全文获取类型
收费全文 | 190970篇 |
免费 | 8546篇 |
国内免费 | 7196篇 |
专业分类
化学 | 90609篇 |
晶体学 | 2278篇 |
力学 | 13287篇 |
综合类 | 474篇 |
数学 | 45086篇 |
物理学 | 54978篇 |
出版年
2023年 | 1076篇 |
2022年 | 2276篇 |
2021年 | 2704篇 |
2020年 | 2979篇 |
2019年 | 3092篇 |
2018年 | 13443篇 |
2017年 | 13168篇 |
2016年 | 10042篇 |
2015年 | 3953篇 |
2014年 | 4666篇 |
2013年 | 6318篇 |
2012年 | 10181篇 |
2011年 | 17022篇 |
2010年 | 10743篇 |
2009年 | 11052篇 |
2008年 | 11947篇 |
2007年 | 13681篇 |
2006年 | 4970篇 |
2005年 | 5437篇 |
2004年 | 5126篇 |
2003年 | 5169篇 |
2002年 | 4348篇 |
2001年 | 3215篇 |
2000年 | 2645篇 |
1999年 | 2172篇 |
1998年 | 2016篇 |
1997年 | 1748篇 |
1996年 | 1804篇 |
1995年 | 1460篇 |
1994年 | 1486篇 |
1993年 | 1380篇 |
1992年 | 1291篇 |
1991年 | 1336篇 |
1990年 | 1291篇 |
1989年 | 1207篇 |
1988年 | 1071篇 |
1987年 | 1035篇 |
1986年 | 996篇 |
1985年 | 1008篇 |
1984年 | 988篇 |
1983年 | 883篇 |
1982年 | 853篇 |
1979年 | 847篇 |
1978年 | 846篇 |
1977年 | 824篇 |
1976年 | 935篇 |
1975年 | 828篇 |
1974年 | 855篇 |
1973年 | 872篇 |
1972年 | 769篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
151.
The anomalous proximity effect between a d-wave superconductor and a thin disordered normal layer is studied theoretically in the framework of Eilenberger equations.
It is shown that disorder of the quasiparticle reflection from this thin layer leads to the formation of an s-wave component localized near the boundary. The angular and spatial structure of the pair potential near the interface is
studied.
Pis’ma Zh. éksp. Teor. Fiz. 67, No. 7, 478–483 (10 April 1998)
Published in English in the original Russian journal. Edited by Steve Torstveit. 相似文献
152.
We present a variational treatment for the E × e pseudo Jahn-Teller system. Through canonical transformation the electron and phonon states are decoupled. An analytical form is obtained for the ground state energy by scaling transformation. Including both the dynamical displacement of phonon modes and the softening of phonon frequency, this approach yields fairly accurate results for the ground state energy. The energy splitting and Ham's reduction factor are calculated, which also generates fairly good results compared with other perturbation results. We argue that our variational wave function is valid for the weak and intermediate coupling range. 相似文献
153.
Space time-index plots for probing dynamical nonstationarity 总被引:3,自引:0,他引:3
We propose a simple method to efficiently probe dynamical nonstationarity in observed time series. In a space time-index plot, the density distributions as a function of normalized time-index are V-shaped due to nonstationarity. We show that this method is workable for short data sets and typical examples are illustrated. 相似文献
154.
155.
纳米硅量子线的发现与研究 总被引:5,自引:0,他引:5
一维纳米材料是当今介观物理学研究的前沿领域.文章报道了一种利用脉冲激光成功地制备纯度高、直径分布均匀的纳米硅量子线(SiNWs)的方法,介绍了纳米量子线的形貌、显微结构、生长机理和物理性能研究的最新结果.纳米硅量子线的发现具有重要的科学意义和潜在的应用前景. 相似文献
156.
It has been shown by Yu. M. Golubev, M. I. Kolobov, and I. V. Sokolov, Zh. éksp. Teor. Fiz. 111, 1579 (1997) [JETP 84, 864 (1997)], that when an optical cavity is excited by external radiation from a sub-Poisson laser the cavity mode may be
in either a sub-Poisson or a Poisson stationary state. This is not important for a resonant medium which is excited into the
upper laser level while interacting with this mode inside the cavity. The degree of regularity of the excitation will be identical
to that of the initial light flux incident on the cavity, and this ultimately ensures the same sub-Poisson lasing as for strictly
regular pumping of the resonant medium.
Zh. éksp. Teor. Fiz. 113, 1223–1234 (April 1998) 相似文献
157.
V. I. Grafutin V. L. Grishkin G. G. Myasishcheva Yu. V. Funtikov Yu. A. Novikov 《Physics of the Solid State》1998,40(4):549-551
The empirical relation θ
p
6
/I
p=aK (where θ
p is the limiting angle of the parabolic component in the angular distributions of annihilation photons in metals, I
p is the integrated contribution of this component, K=1, 2, 3, ... is an integer, and a is a constant independent of the type of metal) observed earlier has been tested on magnesium, aluminum, copper, zinc, lead,
and bismuth samples. The validity of this relation has been substantiated. The value of the dimensionless constant a has been determined and was found to coincide within experimental error with the result obtained in previous measurements.
It is shown that the value of K for the same metal but for different samples may be different. It is conjectured that this may be due to different defect
concentrations in samples.
Fiz. Tverd. Tela (St. Petersburg) 40, 600–602 (April 1998) 相似文献
158.
Lizeng Wang Chengsong Ma Xiaoli Zhang Yibing Ren Yong Yu 《Fresenius' Journal of Analytical Chemistry》1995,351(7):689-691
The electrochemical behavior of the copper-tyrosine complex has been studied by linear-sweep adsorption voltammetry. In 0.02 mol/L Na2HPO4 buffer solution (pH=9.6), the complex can be adsorped on a hanging mercury drop electrode and reduced at a peak potential of about –0.42 V (vs. SCE). The secondary derivative peak height is linear proportional to the concentration of tyrosine in the range 1.0×10–7–5.0×10–5 mol/L. The detection limit is 5×10–8 mol/L.Project supported by the Provincial Science Foundation of Shandong Province 相似文献
159.
160.