全文获取类型
收费全文 | 386篇 |
免费 | 3篇 |
专业分类
化学 | 131篇 |
晶体学 | 3篇 |
数学 | 32篇 |
物理学 | 223篇 |
出版年
2020年 | 8篇 |
2013年 | 5篇 |
2012年 | 9篇 |
2011年 | 4篇 |
2008年 | 4篇 |
2007年 | 9篇 |
2006年 | 11篇 |
2004年 | 6篇 |
2003年 | 7篇 |
2002年 | 4篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 4篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 7篇 |
1994年 | 11篇 |
1992年 | 11篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 7篇 |
1988年 | 8篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 11篇 |
1983年 | 14篇 |
1982年 | 15篇 |
1981年 | 12篇 |
1980年 | 8篇 |
1979年 | 12篇 |
1978年 | 10篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1975年 | 9篇 |
1974年 | 4篇 |
1973年 | 7篇 |
1972年 | 6篇 |
1971年 | 6篇 |
1970年 | 6篇 |
1964年 | 3篇 |
1959年 | 3篇 |
1956年 | 4篇 |
1934年 | 3篇 |
1933年 | 5篇 |
1932年 | 3篇 |
1929年 | 3篇 |
1924年 | 5篇 |
1893年 | 3篇 |
1891年 | 3篇 |
排序方式: 共有389条查询结果,搜索用时 187 毫秒
81.
H.‐H. Klauß M. Hillberg W. Wagener M.A.C. de Melo F.J. Litterst M. Fricke J. Hesse E. Schreier 《Hyperfine Interactions》1997,104(1-4):319-323
The spin dynamics in the reentrant spin glass ( Fe0.65 Ni0.35)1-x Mn_x has been studied by zero, longitudinal and transverse field μSR. In the ferromagnetic reentrant and pure spin glass
regimes (x\leqslant 0.175), zero field experiments reveal a stretched exponential muon relaxation with a universal behaviour
of the dynamic exponent \beta above the spin glass transition. There are no qualitative differences between the ferromagnetic
and paramagnetic phases. In transversal field μSR experiments the divergence of the relaxation rate close to the spin glass
transition is suppressed for manganese doping up to x=0.113 but enhanced for slightly higher doping (x\geqslant 0.12). We
understand this behaviour as a crossover from an itinerant to a more localized state of the 3d electron system. This is also
supported by the fact that in the highly doped regime with dominant antiferromagnetic interactions the muon relaxation rate
diverges above the antiferromagnetic transition temperature.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
82.
D. Verney L. Cabaret J. E. Crawford H. T. Duong B. Fricke J. Genevey G. Huber F. Ibrahim M. Krieg F. Le Blanc J. K. P. Lee G. Le Scornet D. Lunney J. Obert J. Oms J. Pinard J. C. Puteaux K. Rashid B. Roussière J. Sauvage V. Sebastian 《The European Physical Journal A - Hadrons and Nuclei》2006,30(3):489-518
Laser spectroscopy measurements have been performed on neutron-deficient and stable Ir isotopes using the COMPLIS experimental
setup installed at ISOLDE-CERN. The radioactive Ir atoms were obtained from successive decays of a mass-separated Hg beam
deposited onto a carbon substrate after deceleration to 1kV and subsequently laser desorbed. A three-color, two-step resonant
scheme was used to selectively ionize the desorbed Ir atoms. The hyperfine structure (HFS) and isotope shift (IS) of the first
transition of the ionization path 5d
76s
24
F
9/2 → 5d
76s6p
6
F
11/2 at 351.5nm were measured for 182-189Ir, 186Ir
m
and the stable 191, 193Ir. The nuclear magnetic moments μI and the spectroscopic quadrupole moments Qs were obtained from the HFS spectra and the change of the mean square charge radii from the IS measurements. The sign of μI was experimentally determined for the first time for the masses 182≤A≤189 and the isomeric state 186Ir
m
. The spectroscopic quadrupole moments of 182Ir and 183Ir were measured also for the first time. A large mean square charge radius change between 187Ir and 186Ir
g
and between 186Ir
m
and 186Ir
g
was observed corresponding to a sudden increase in deformation: from β2 ≃ + 0.16 for the heavier group A = 193, 191, 189, 187 and 186m to β2≥ + 0.2 for the lighter group A = 186g, 185, 184, 183 and 182. These results were analyzed in the framework of a microscopic treatment of an axial rotor plus one
or two quasiparticle(s). This sudden deformation change is associated with a change in the proton state that describes the
odd-nuclei ground state or that participates in the coupling with the neutron in the odd-odd nuclei. This state is identified
with the π3/2+[402] orbital for the heavier group and with the π1/2-[541] orbital stemming from the 1h
9/2 spherical subshell for the lighter group. That last state seems to affect strongly the observed values of the nuclear moments. 相似文献
83.
J. Fricke 《Journal of Non》1988,100(1-3):169-173
84.
85.
Robert Fricke 《Mathematische Annalen》1887,30(3):345-400
Ohne Zusammenfassung 相似文献
86.
87.
88.
W. Eckstein S. Hackel D. Heinemann B. Fricke 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1992,24(2):171-176
The TRIM.SP program which is based on the binary collision approximation was changed to handle not only repulsive interaction potentials, but also potentials with an attractive part. Sputtering yields, average depth and reflection coefficients calculated with four different potentials are compared. Three purely repulsive potentials (Molière, Kr-C and ZBL) are used and an ab initio pair potential, which is especially calculated for silicon bombardment by silicon. The general trends in the calculated results are similar for all potentials applied, but differences between the repulsive potentials and the ab initio potential occur for the reflection coefficients and the sputtering yield at large angles of incidence. 相似文献
89.
90.
LetP m denote an equilateral polygon ofm sides with each side having length 1 and we allow the sides to cross and vertex repetitions. We consider the following question. What is the smallest widtht m of a horizontal strip in the Euclidean plane that contains aP m ? This problem has its origins in Euclidean Ramsey theory. Whenm is even, it is easy to see thatt m =0. For a polygon with an odd number of sides, we prove that $\begin{gathered} t_{2n + 1} = \frac{{\sqrt {2n + 1} }}{{n + 1}} for 2n + 1 \equiv 3(\bmod 4) and \hfill \\ t_{2n + 1} = \sqrt {\frac{{2n + 1}}{{n^2 + 2n}}} for 2n + 1 \equiv 1(\bmod 4) \hfill \\ \end{gathered} $ respectively. Applying the result to unit distance graphs, we prove the following: SupposeG is a unit-distance graph, i.e.G can be drawn on the planeR 2 such that each edge ofG is a straight line segment of length 1. IfG has no odd circuits of length greater than or equal to 15, thenX(G) ≤ 6, whereX(G) is the chromatic number ofG. 相似文献