全文获取类型
收费全文 | 39500篇 |
免费 | 1340篇 |
国内免费 | 272篇 |
专业分类
化学 | 27158篇 |
晶体学 | 301篇 |
力学 | 788篇 |
综合类 | 1篇 |
数学 | 6473篇 |
物理学 | 6391篇 |
出版年
2022年 | 288篇 |
2021年 | 448篇 |
2020年 | 647篇 |
2019年 | 631篇 |
2018年 | 441篇 |
2017年 | 414篇 |
2016年 | 1008篇 |
2015年 | 878篇 |
2014年 | 1061篇 |
2013年 | 1899篇 |
2012年 | 2332篇 |
2011年 | 2662篇 |
2010年 | 1441篇 |
2009年 | 1270篇 |
2008年 | 2443篇 |
2007年 | 2331篇 |
2006年 | 2316篇 |
2005年 | 2174篇 |
2004年 | 1904篇 |
2003年 | 1529篇 |
2002年 | 1456篇 |
2001年 | 594篇 |
2000年 | 577篇 |
1999年 | 469篇 |
1998年 | 447篇 |
1997年 | 476篇 |
1996年 | 518篇 |
1995年 | 370篇 |
1994年 | 434篇 |
1993年 | 416篇 |
1992年 | 412篇 |
1991年 | 349篇 |
1990年 | 326篇 |
1989年 | 277篇 |
1988年 | 259篇 |
1987年 | 284篇 |
1986年 | 244篇 |
1985年 | 480篇 |
1984年 | 421篇 |
1983年 | 351篇 |
1982年 | 411篇 |
1981年 | 356篇 |
1980年 | 346篇 |
1979年 | 306篇 |
1978年 | 291篇 |
1977年 | 279篇 |
1976年 | 262篇 |
1975年 | 253篇 |
1974年 | 230篇 |
1973年 | 201篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
C. Michael 《The European Physical Journal A - Hadrons and Nuclei》2003,18(2-3):257-260
Lattice QCD can give direct information on OZI-violating contributions to mesons. Here we explore the contributions that split flavour singlet and non-singlet meson masses. I discuss in detail the spectrum and decays for scalar mesons (i.e. including glueball effects). I also review the status of hybrid mesons and their decays.Received: 30 September 2002, Published online: 22 October 2003PACS:
12.38.Gc Lattice QCD calculations - 12.39.Mk Glueball and nonstandard multi-quark/gluon states 相似文献
42.
43.
Michael T. Jury David W. Kribs 《Proceedings of the American Mathematical Society》2005,133(1):213-222
Given a row contraction of operators on a Hilbert space and a family of projections on the space that stabilizes the operators, we show there is a unique minimal joint dilation to a row contraction of partial isometries that satisfy natural relations. For a fixed row contraction the set of all dilations forms a partially ordered set with a largest and smallest element. A key technical device in our analysis is a connection with directed graphs. We use a Wold decomposition for partial isometries to describe the models for these dilations, and we discuss how the basic properties of a dilation depend on the row contraction.
44.
Michael De Castro 《Tetrahedron letters》2004,45(34):6501-6504
2-Deoxy-2-iodo-glycosylamides have been prepared from a variety of protected d-glucals by their reaction with N-iodosuccinimide and amides. Benzyl protected 2-iodoamides, when treated with sodium hydride and 15-crown-5, gave stable C1 N-linked 2-glycooxazolines as the major products. Silyl protected 2-iodoamides afforded the C1 O-linked 2-glycooxazolines; presumably by the rearrangement of unstable N-acylaziridine intermediates. 相似文献
45.
Palladium-catalysed three component coupling of an alkenylbromide, isonitrile and an amine or alkoxide/phenoxide affords α,β-unsaturated-amidines and -imidates. 相似文献
46.
Ohne Zusammenfassung
Dem Andenken von Leo Lichtenstein gewidmet. 相似文献
47.
48.
Richard Brown 《Geometriae Dedicata》2003,97(1):129-150
In this note, we show that given a closed, orientable genus-g surface S
g
, any hyperbolic toral automorphism has a positive power which induces a quadratic, orientable pseudo-Anosov homeomorphism on S
g
. To show this, we lift Anosov toral automorphisms through a ramified topological covering and present the lifted homeomorphism via a standard set of Lickorish twists. This construction provides a general method of producing pseudo-Anosov maps of closed surfaces with predetermined orientable foliations and quadratic dilatation. Since these lifted automorphisms have orientable foliations, this construction is a sort of converse to that of Franks and Rykken [Trans. Amer. Math. Soc. 1999], who established that one can associate to a quadratic pseudo-Anosov homeomorphism with oriented unstable foliation a hyperbolic toral automorphism. 相似文献
49.
50.
Michael Struwe 《Calculus of Variations and Partial Differential Equations》2003,16(4):431-437
Extending our previous work [5] on this subject we show global existence of smooth solutions to the Cauchy problem for wave
maps from the (1 + 2)-dimensional Minkowski space to an arbitrary smooth, compact Riemannian manifold without boundary, for
arbitrary smooth, radially symmetric data.
Received: 14 December 2001 / Accepted: 1 March 2002 / Published online: 6 August 2002 相似文献