全文获取类型
收费全文 | 1524篇 |
免费 | 20篇 |
国内免费 | 9篇 |
专业分类
化学 | 828篇 |
晶体学 | 7篇 |
力学 | 57篇 |
数学 | 231篇 |
物理学 | 430篇 |
出版年
2020年 | 20篇 |
2016年 | 20篇 |
2015年 | 16篇 |
2014年 | 22篇 |
2013年 | 55篇 |
2012年 | 53篇 |
2011年 | 56篇 |
2010年 | 38篇 |
2009年 | 37篇 |
2008年 | 57篇 |
2007年 | 46篇 |
2006年 | 55篇 |
2005年 | 47篇 |
2004年 | 40篇 |
2003年 | 39篇 |
2002年 | 51篇 |
2001年 | 26篇 |
2000年 | 28篇 |
1999年 | 29篇 |
1998年 | 14篇 |
1997年 | 14篇 |
1996年 | 20篇 |
1995年 | 26篇 |
1994年 | 12篇 |
1993年 | 38篇 |
1992年 | 18篇 |
1991年 | 28篇 |
1990年 | 22篇 |
1989年 | 20篇 |
1988年 | 14篇 |
1987年 | 24篇 |
1986年 | 16篇 |
1985年 | 20篇 |
1984年 | 21篇 |
1983年 | 12篇 |
1982年 | 15篇 |
1981年 | 20篇 |
1980年 | 19篇 |
1978年 | 20篇 |
1977年 | 31篇 |
1976年 | 19篇 |
1975年 | 16篇 |
1974年 | 14篇 |
1973年 | 16篇 |
1971年 | 18篇 |
1970年 | 12篇 |
1968年 | 18篇 |
1967年 | 15篇 |
1966年 | 15篇 |
1931年 | 12篇 |
排序方式: 共有1553条查询结果,搜索用时 31 毫秒
61.
S. Issing F. Fuchs C. Ziereis E. Batke A. Pimenov Y. Vu. Ivanov A. A. Mukhin J. Geurts 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,73(3):353-360
A systematic and detailed study of Raman and infrared active lattice excitations in the orthorhombic multiferroic manganite
Eu1−xYxMnO3 (0 ≤ x ≤ 0.5) was carried out at room temperature. For the infrared active phonon modes the eigenfrequencies, damping constants
and oscillator strengths were analyzed by Fourier-Transform Infrared Spectroscopy in the far infrared frequency range. For
the Raman active phonons the same analysis for eigenfrequencies and damping constants was carried out using Raman spectroscopy
in the range from 200 cm−1 to 700 cm−1. Y doping leads to mode-dependent phonon frequency shifts up to 8%. These are interpreted in terms of the interplay between
the decrease of the reduced ion masses and the axis-dependent change of bond lengths. The latter leads to a bond softening
along the a-axis and a strengthening along the c-axis, for which the highest phonon frequency increase is observed. The application
of both Raman and Infrared Spectroscopy gives us sensitivity not only to symmetry properties via the selection rules but also
to the involvement of different ion types within the unit cell. It is clearly shown that the disorder induced effects are
of minor impact on the lattice properties and solely detected on the rare earth sites. The MnO6 octahedra remain unaffected and show the same behavior as in the stochiometric RMnO3 making Eu1−xYxMnO3 an excellent model system for a quasi-continuous fine-tuning of the lattice parameters relevant for the appearance of multiferroicity. 相似文献
62.
A. Fuchs M. Bender U. Plachetka L. Kock N. Koo T. Wahlbrink H. Kurz 《Current Applied Physics》2008,8(6):669-674
In the past decade nanoimprint has been developed to a serious alternative for next generation lithography (NGL). In this work, the most recent developments of UV-nanoimprint Lithography (UV-NIL) with special emphasis to the work accomplished at AMO and the IHT-RWTH Aachen are reviewed and functional applications demonstrated. Further the potentials of various UV-NIL concepts are evaluated and possible interests in certain application areas are discussed. 相似文献
63.
Michael Bildhauer Martin Fuchs Victor Osmolovskii 《Mathematical Methods in the Applied Sciences》2002,25(2):149-178
We consider the problem of minimizing among functions u:?d?Ω→?d, u∣?Ω=0, and measurable subsets E of Ω. Here fh+, f? denote quadratic potentials defined on Ω¯×{symmetric d×d matrices}, h is the minimum energy of fh+ and ε(u) is the symmetric gradient of the displacement field u. An equilibrium state û, Ê of J(u,E) is called one‐phase if E=?? or E=Ω, two‐phase otherwise. For two‐phase states, σ∣?E∩Ω∣ measures the effect of the separating surface, and we investigate the way in which the distribution of phases is affected by the choice of the parameters h??, σ>0. Additional results concern the smoothness of two‐phase equilibrium states and the behaviour of inf J(u,E) in the limit σ↓0. Moreover, we discuss the case of additional volume force potentials, and extend the previous results to non‐zero boundary values. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
64.
M. Bildhauer M. Fuchs V. G. Osmolovskii 《Mathematical Methods in the Applied Sciences》2002,25(4):289-308
We consider the problem of minimizing 0<p<1, h∈?, σ>0, among functions u:?d?Ω→?d, u∣?Ω=0, and measurable characteristic functions χ:Ω→?. Here ?+h, ??, denote quadratic potentials defined on the space of all symmetric d×d matrices, h is the minimum energy of ?+h and ε(u) denotes the symmetric gradient of the displacement field. An equilibrium state û, χ?, of I [·,·,h, σ] is termed one‐phase if χ?≡0 or χ?≡1, two‐phase otherwise. We investigate the way in which the distribution of phases is affected by the choice of the parameters h and σ. Copyright 2002 John Wiley & Sons, Ltd. 相似文献
65.
66.
Eriksson LG Fourment C Fuchs V Litaudon X Challis CD Crisanti F Esposito B Garbet X Giroud C Hawkes N Maget P Mazon D Tresset G 《Physical review letters》2002,88(14):145001
Joint European Torus discharges which demonstrate the critical role the safety factor profile, q, can play in the formation of internal transport barriers (ITB) are examined. In these discharges, the target parameters, including the E x B flows, were kept virtually the same, except for the q profile. In a discharge with a nonmonotonic q, an ITB was triggered whereas a discharge with monotone q made no such transition. Thus, there is strong evidence that the q profile was the critical factor for the triggering of an ITB. Possible interpretations of this finding are discussed. 相似文献
67.
Fuchs J Labaune C Bandulet H Michel P Depierreux S Baldis HA 《Physical review letters》2002,88(19):195003
We present direct measurements of the coherence time of a laser beam after propagation through an underdense plasma. At an intensity of 10(14) W/cm(2), a large decrease of the coherence time is observed, from 300 ps to a few picoseconds. This decrease is larger as the plasma density is increased or as the light is scattered at larger angles. The amount of temporal decorrelation as well as the effect of the plasma density, laser intensity, and scattering angle all coincide with trends observed in recent numerical simulations. 相似文献
68.
69.
70.
O. Fuchs 《Fresenius' Journal of Analytical Chemistry》1968,237(4):290-280
Ohne Zusammenfassung 相似文献