全文获取类型
收费全文 | 167篇 |
免费 | 1篇 |
专业分类
化学 | 95篇 |
力学 | 1篇 |
数学 | 10篇 |
物理学 | 62篇 |
出版年
2023年 | 2篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2015年 | 1篇 |
2013年 | 21篇 |
2012年 | 11篇 |
2011年 | 9篇 |
2010年 | 8篇 |
2009年 | 2篇 |
2008年 | 2篇 |
2007年 | 8篇 |
2006年 | 4篇 |
2005年 | 9篇 |
2004年 | 2篇 |
2003年 | 5篇 |
2002年 | 1篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 6篇 |
1996年 | 1篇 |
1995年 | 8篇 |
1993年 | 4篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1967年 | 4篇 |
1962年 | 1篇 |
1948年 | 1篇 |
1939年 | 1篇 |
1938年 | 2篇 |
1935年 | 1篇 |
1934年 | 1篇 |
1933年 | 1篇 |
1932年 | 1篇 |
1931年 | 4篇 |
1924年 | 2篇 |
排序方式: 共有168条查询结果,搜索用时 15 毫秒
21.
B. Pedrini S. Wessel J. L. Gavilano H. R. Ott S. M. Kazakov J. Karpinski 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,55(3):219-228
We report results of susceptibility χ and 7Li NMR measurements on LiVSi2O6. The temperature dependence of the magnetic susceptibility χ(T) exhibits a broad maximum, typical for low-dimensional magnetic
systems. Quantitatively it is in agreement with the expectation for an S=1 spin chain, represented by the structural arrangement
of V ions.
The NMR results indicate antiferromagnetic ordering below TN=24 K. The intra- and interchain coupling J and Jp for LiVSi2O6, and also for its sister compounds LiVGe2O6, NaVSi2O6 and NaVGe2O6, are obtained via a modified random phase approximation which takes into account results of quantum Monte Carlo calculations.
While Jp is almost constant across the series, J varies by a factor of 5, decreasing with increasing lattice constant along the chain
direction. The comparison between experimental and theoretical susceptibility data suggests the presence of an easy-axis magnetic
anisotropy, which explains the formation of an energy gap in the magnetic excitation spectrum below TN, indicated by the variation of the NMR spin-lattice relaxation rate at T≪TN. 相似文献
22.
23.
24.
A. Stork C. Wessel A. Börger K.-D. Becker M. Lerch 《Journal of solid state chemistry》2010,183(9):2051-2058
The aim of our study was to modify the basis compound ß-TaON, which crystallizes in the monoclinic baddeleyite-type, by incorporation of appropriate dopant ions, in order to obtain anion-deficient cubic fluorite-type phases, which are of interest as solids with mobile nitrogen ions. For this purpose, scandium-doped tantalum oxide nitrides were prepared by ammonolysis of amorphous oxide precursors. An unexpected variety of phases with different structural features was observed: bixbyite-type phases of general composition ScxTa1−x(O,N)y with 0.33≤x≤1 and 1.7≤y≤1.9, yellow colored metastable anatase-type phases such as Sc0.1Ta0.9O1.2N0.8 or Sc0.15Ta0.85O1.3N0.7 and, additionally, anosovite-type phases ScxTa3−xO2xN5−2x with 0≤x≤1.05. Selected phases were investigated by UV/vis spectroscopy. Anatase- and anosovite-type compounds show brilliant colors. In the anatase-type phase, a possible anion ordering was examined by theoretical methods. Additionally, energy calculations on phase stability were performed for ScxTa1−xO1+2xN1−2x in the baddeleyite, rutile, and anatase structure types with varying amounts of dopants. 相似文献
25.
26.
27.
R. Edge M. François L. Seguin M. Kessler J. Houben Leslie Hart F. P. Treadwell H. Biltz W. Biltz und F. Wessel 《Fresenius' Journal of Analytical Chemistry》1931,85(7-8):307-320
Ohne Zusammenfassung 相似文献
28.
29.
Femke Douma 《Discrete Mathematics》2011,(4):276
Huber (1956) [8] considered the following problem on the hyperbolic plane H. Consider a strictly hyperbolic subgroup of automorphisms on H with compact quotient, and choose a conjugacy class in this group. Count the number of vertices inside an increasing ball, which are images of a fixed point x∈H under automorphisms in the chosen conjugacy class, and describe the asymptotic behaviour of this number as the size of the ball goes to infinity. We use a well-known analogy between the hyperbolic plane and the regular tree to solve this problem on the regular tree. 相似文献
30.
H. Gimperlein S. Wessel J. Schmiedmayer L. Santos 《Applied physics. B, Lasers and optics》2006,82(2):217-224
We consider the physics of lattice bosons in the presence of either disordered on-site chemical potential or disordered on-site
interparticle interactions. By means of analytical results using strong-coupling expansion, and numerical results based on
quantum Monte Carlo calculations, we show that important qualitative changes in the zero temperature phase diagram are observed
when comparing both cases. Although for both types of disorder superfluid, Mott-insulator and Bose-glass phases may be found,
we show that in the case of random interactions the Mott-insulating regions shrink and eventually vanish for any finite disorder
strength beyond a sufficiently large filling factor. Furthermore, at low values of the chemical potential both the superfluid
and Mott insulator are stable towards the formation of a Bose-glass, leading to a possibly non-trivial tricritical point.
We discuss possible experimental realizations of both types of disorder in the context of ultra cold atomic gases in optical
lattices.
PACS 03.75.Lm; 03.75.Ss; 05.30.Jp; 32.80.Pj 相似文献