全文获取类型
收费全文 | 7165篇 |
免费 | 275篇 |
国内免费 | 31篇 |
专业分类
化学 | 4469篇 |
晶体学 | 35篇 |
力学 | 196篇 |
综合类 | 3篇 |
数学 | 1032篇 |
物理学 | 1736篇 |
出版年
2023年 | 46篇 |
2022年 | 51篇 |
2021年 | 82篇 |
2020年 | 110篇 |
2019年 | 108篇 |
2018年 | 98篇 |
2017年 | 84篇 |
2016年 | 184篇 |
2015年 | 145篇 |
2014年 | 186篇 |
2013年 | 392篇 |
2012年 | 388篇 |
2011年 | 450篇 |
2010年 | 236篇 |
2009年 | 200篇 |
2008年 | 370篇 |
2007年 | 380篇 |
2006年 | 367篇 |
2005年 | 369篇 |
2004年 | 278篇 |
2003年 | 263篇 |
2002年 | 252篇 |
2001年 | 172篇 |
2000年 | 128篇 |
1999年 | 93篇 |
1998年 | 73篇 |
1997年 | 95篇 |
1996年 | 73篇 |
1995年 | 78篇 |
1994年 | 62篇 |
1993年 | 73篇 |
1992年 | 68篇 |
1991年 | 58篇 |
1990年 | 44篇 |
1989年 | 48篇 |
1988年 | 54篇 |
1986年 | 51篇 |
1985年 | 72篇 |
1984年 | 70篇 |
1983年 | 66篇 |
1982年 | 97篇 |
1981年 | 78篇 |
1980年 | 69篇 |
1979年 | 73篇 |
1978年 | 78篇 |
1977年 | 69篇 |
1976年 | 73篇 |
1975年 | 65篇 |
1974年 | 66篇 |
1973年 | 55篇 |
排序方式: 共有7471条查询结果,搜索用时 15 毫秒
41.
42.
43.
Interplay of charge, spin, orbital and lattice correlations in colossal magnetoresistance manganites
A. Weiße H. Fehske 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,30(4):487-494
We derive a realistic microscopic model for doped colossal magnetoresistance manganites, which includes the dynamics of charge,
spin, orbital and lattice degrees of freedom on a quantum mechanical level. The model respects the SU(2) spin symmetry and the full multiplet structure of the manganese ions within the cubic lattice. Concentrating on the hole
doped domain ( 0≤x≤0.5) we study the influence of the electron-lattice interaction on spin and orbital correlations by means of exact diagonalisation
techniques. We find that the lattice can cause a considerable suppression of the coupling between spin and orbital degrees
of freedom and show how changes in the magnetic correlations are reflected in dynamic phonon correlations. In addition, our
calculation gives detailed insights into orbital correlations and demonstrates the possibility of complex orbital states.
Received 4 September 2002 / Received in final form 8 November 2002 Published online 31 December 2002 相似文献
44.
Dilyana Paneva Laetitia Mespouille Nevena Manolova Philippe Dege Iliya Rashkov Philippe Dubois 《Journal of polymer science. Part A, Polymer chemistry》2006,44(19):5468-5479
Polyelectrolyte complexes (PECs) have been prepared from well‐defined (quaternized) poly[2‐(dimethylamino)ethyl methacrylate] (PDMAEMA) and high molecular weight poly(2‐acrylamido‐2‐methylpropane sodium sulfonate) (PAMPSNa) after a thorough study of their viscometric properties. The effect of pH and quaternization degree of PDMAEMA on PECs stoichiometry has been examined. PEC‐based materials have been characterized in terms of thermal stability, equilibrium swelling degree, and free/bound water composition. The stoichiometry and swellability of the physically crosslinked hydrogels obtained from fully quaternized PDMAEMA/PAMPSNa complexes do not depend on pH. In contrast, PECs made of non quaternized PDMAEMA and PAMPSNa are highly affected by pH, and could reversibly disintegrate at pH ≥ 9. Partially quaternized PDMAEMA/PAMPSNa PECs exhibit intermediate properties and form stable loose structures in the whole investigated pH range. Finally, stable dispersions of PECs nanoparticles have been successfully produced from dilute solutions of the complementary polyelectrolytes. The nanoparticle average diameter as determined by dynamic light scattering proved to depend on the molar fraction of DMAEMA‐based subunits and on the initial polyelectrolyte concentration. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5468–5479, 2006 相似文献
45.
46.
We discuss role of partially gravitating scalar fields, scalar fields whose energy–momentum tensors vanish for a subset of dimensions, in dynamical compactification of a given set of dimensions. We show that the resulting spacetime exhibits a factorizable geometry consisting of usual four-dimensional spacetime with full Poincaré invariance times a manifold of extra dimensions whose size and shape are determined by the scalar field dynamics. Depending on the strength of its coupling to the curvature scalar, the vacuum expectation value (VEV) of the scalar field may or may not vanish. When its VEV is zero the higher-dimensional spacetime is completely flat and there is no compactification effect at all. On the other hand, when its VEV is nonzero the extra dimensions get spontaneously compactified. The compactification process is such that a bulk cosmological constant is utilized for curving the extra dimensions. 相似文献
47.
We compute the entropyh
A
(
U
) in the sense of Connes, Narnhofer and Thirring of Bogoliubov automorphisms
U
of the CAR-algebra with respect to invariant quasifree states
A
with 0A1 having pure point spectrum.Supported in part by a grant from the National Science Foundation 相似文献
48.
Bent Fuglede 《Communications in Mathematical Physics》1990,129(3):481-509
The integral of a function over then'th power of hyperbolicd-dimensional spaceH is decomposed into integration along each orbit under diagonal action onH
n of the isometry groupG onH, followed by integration over the orbit space, parametrized in terms of a complete set of invariants. The Jacobian entering in this last integral is expressed explicitly in terms of certain determinants. When viewingH as a half-hyperboloid in
d+1
,G is induced by the homogeneous Lorentz groupO
(1,d) acting on
d+1
. 相似文献
49.
50.
Ong RA Weir AJ Abrams GS Amidei D Baden AR Barklow T Boyarski AM Boyer J Burchat PR Burke DL Butler F Dorfan JM Feldman GJ Gidal G Gladney L Gold MS Goldhaber G Golding L Haggerty J Hanson G Hayes K Herrup D Hollebeek RJ Innes WR Jaros JA Juricic I Kadyk JA Karlen D Klein SR Lankford AJ Larsen RR LeClaire BW Levi M Lockyer NS Lüth V Nelson ME Perl ML Petersen A Richter B Riles K Rowson PC Schaad T Schellman H Schmidke WB Sheldon PD Trilling GH Wood DR Yelton JM 《Physical review letters》1988,60(25):2587-2590