全文获取类型
收费全文 | 1388篇 |
免费 | 57篇 |
专业分类
化学 | 714篇 |
晶体学 | 14篇 |
力学 | 40篇 |
数学 | 211篇 |
物理学 | 466篇 |
出版年
2023年 | 13篇 |
2022年 | 10篇 |
2021年 | 11篇 |
2020年 | 18篇 |
2019年 | 36篇 |
2018年 | 36篇 |
2017年 | 37篇 |
2016年 | 74篇 |
2015年 | 48篇 |
2014年 | 69篇 |
2013年 | 111篇 |
2012年 | 65篇 |
2011年 | 77篇 |
2010年 | 53篇 |
2009年 | 59篇 |
2008年 | 66篇 |
2007年 | 37篇 |
2006年 | 36篇 |
2005年 | 21篇 |
2004年 | 34篇 |
2003年 | 31篇 |
2002年 | 23篇 |
2001年 | 28篇 |
2000年 | 22篇 |
1999年 | 34篇 |
1998年 | 18篇 |
1997年 | 14篇 |
1996年 | 18篇 |
1995年 | 28篇 |
1994年 | 12篇 |
1993年 | 21篇 |
1992年 | 15篇 |
1991年 | 12篇 |
1990年 | 10篇 |
1989年 | 11篇 |
1988年 | 18篇 |
1987年 | 15篇 |
1986年 | 17篇 |
1985年 | 17篇 |
1984年 | 18篇 |
1983年 | 15篇 |
1982年 | 17篇 |
1981年 | 14篇 |
1979年 | 9篇 |
1978年 | 11篇 |
1977年 | 10篇 |
1976年 | 7篇 |
1975年 | 7篇 |
1974年 | 15篇 |
1973年 | 8篇 |
排序方式: 共有1445条查询结果,搜索用时 46 毫秒
1.
2.
Letg:U→ℝ (U open in ℝn) be an analytic and K-subanalytic (i. e. definable in ℝ
an
K
, whereK, the field of exponents, is any subfield ofℝ) function. Then the set of points, denoted Σ, whereg does not admit an analytic extension is K-subanalytic andg can be extended analytically to a neighbourhood of Ū\∑.
Partially supported by the European RTN Network RAAG (contract no. HPRN-CT-00271) 相似文献
3.
W. Hoheisel U. Schulte M. Vollmer F. Träger 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1991,20(1):381-383
This paper reports new results on the optical spectra of Na particles and on laser-induced photodissociation of Na atoms from the surface of these particles. In continuation of our earlier studies we have performed experiments to elucidate the mechanism of thenonthermal dissociation process. Furthermore, theoretical calculations have been carried out with the goal to correlate the wavelength dependence of the photodissociation yield with the optical absorption spectra of the metal particles. In addition, manipulation of the size distribution of metal particles on supports is outlined as an application of the effect. This allows for the preparation of very special surfaces with novel physical and chemical properties. 相似文献
4.
We study a boundary version of the gauged WZW model with a Poisson–Lie group G as the target. The Poisson–Lie structure of G is used to define the Wess–Zumino term of the action on surfaces with boundary. We clarify the relation of the model to the topological Poisson sigma model with the dual Poisson–Lie group G
* as the target and show that the phase space of the theory on a strip is essentially the Heisenberg double of G introduced by Semenov–Tian–Shansky. 相似文献
5.
In the present paper the problems of existence and uniqueness of almost periodic solutions for impulsive cellular neural networks with delay are considered. 相似文献
6.
7.
Two matrix approximation problems are considered: approximation of a rectangular complex matrix by subunitary matrices with
respect to unitarily invariant norms and a minimal rank approximation with respect to the spectral norm. A characterization
of a subunitary approximant of a square matrix with respect to the Schatten norms, given by Maher, is extended to the case
of rectangular matrices and arbitrary unitarily invariant norms. Iterative methods, based on the family of Gander methods
and on Higham’s scaled method for polar decomposition of a matrix, are proposed for computing subunitary and minimal rank
approximants. Properties of Gander methods are investigated in details.
AMS subject classification (2000) 65F30, 15A18 相似文献
8.
Please forward books for review to the book review editor: Magdolna Hargittai, Structural Chemistry Research Group of the Hungarian Academy of Sciences, Eötvös University, H-1431 Budapest, Pf. 117, Hungary 相似文献
9.
V. V. Sidorchuk J. Skubiszewska-Zięba S. V. Khalameida V. A. Zazhigalov R. Leboda 《Russian Journal of Applied Chemistry》2008,81(8):1325-1331
Effect of conditions of hydrothermal and microwave synthesis of supported vanadium-phosphorus oxide catalysts in an aqueous medium on the physicochemical properties of the vanadyl hydrophosphate obtained was studied. The transformations occurring in the system were examined using X-ray phase and differential-thermal analyses, adsorption-structural method, and scanning electron microscopy. 相似文献
10.
Marek Pękała Jan Mucha Benedicte Vertruyen Rudi Cloots Marcel Ausloos 《Journal of magnetism and magnetic materials》2006
Samples of La0.7Ca0.3Mn1−xGaxO3 with x=0, 0.025, 0.05 and 0.10 were prepared by standard solid-state reaction. They were first characterized chemically, including the microstructure. The magnetic properties and various transport properties, i.e. the electrical resistivity, magnetoresistivity (for a field below 8 T), thermoelectric power and thermal conductivity measured each time on the same sample, are reported. The markedly different behaviour of the x=0.1 sample from those with a smaller Ga content, is discussed. The dilution of the Mn3+/Mn4+ interactions with Ga doping considerably reduces the ferromagnetic double exchange interaction within the manganese lattice leading to a decrease of the Curie temperature. The polaron binding energy varies from 224 to 243 meV with increased Ga doping. 相似文献