全文获取类型
收费全文 | 496篇 |
免费 | 2篇 |
专业分类
化学 | 403篇 |
晶体学 | 2篇 |
数学 | 22篇 |
物理学 | 71篇 |
出版年
2023年 | 2篇 |
2022年 | 6篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2016年 | 7篇 |
2014年 | 3篇 |
2013年 | 13篇 |
2012年 | 10篇 |
2011年 | 18篇 |
2010年 | 8篇 |
2009年 | 10篇 |
2008年 | 21篇 |
2007年 | 28篇 |
2006年 | 26篇 |
2005年 | 20篇 |
2004年 | 18篇 |
2003年 | 23篇 |
2002年 | 32篇 |
2001年 | 8篇 |
2000年 | 8篇 |
1998年 | 8篇 |
1997年 | 4篇 |
1996年 | 10篇 |
1995年 | 2篇 |
1994年 | 7篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 10篇 |
1984年 | 13篇 |
1983年 | 6篇 |
1982年 | 24篇 |
1981年 | 11篇 |
1980年 | 15篇 |
1979年 | 7篇 |
1978年 | 14篇 |
1977年 | 18篇 |
1976年 | 15篇 |
1975年 | 6篇 |
1974年 | 5篇 |
1973年 | 15篇 |
1972年 | 2篇 |
1961年 | 1篇 |
1960年 | 1篇 |
1927年 | 1篇 |
排序方式: 共有498条查询结果,搜索用时 15 毫秒
471.
Izumi Ojima 《Letters in Mathematical Physics》1986,11(1):73-80
The Lorentz invariance of a relativistic QFT is shown to be broken spontaneously at finite temperature with a zero-energy Goldstone spectrum which does not necessarily carry a one-particle structure. The Lorentz behaviour of the temperature is determined and the relation between Gibbs states in different Lorentz frames is clarified. 相似文献
472.
473.
The theorem stating the absence of localized charged physical states in QED is extended to QCD in the manifestly covariant canonical formalism. The correct relation between the Gupta-Bleuler condition and the coherent photon states associated to the charged sectors is clarified in the case of QED, which secures the existence of electrons as non-localized charged physical states. 相似文献
474.
Zeitschrift für Physik C Particles and Fields - 相似文献
475.
476.
Masahiro Ojima Yasuo Oka Takashi Kushida Shigeo Shionoya 《Solid State Communications》1977,24(12):845-848
Luminescence spectra of excitonic molecules in CuCl resonantly created by nano-second dye laser excitation are measured at 4.2 K changing the lenghts of the excited region. The spectra are dominated by stimulated emission. The gain coefficient for the MT line is saturated more easily than that for ML, though the former is larger under unsaturated conditions. These gain characteristics explain well various stimulated emission effects observed. 相似文献
477.
478.
1,3-Diemthyl(5H,7H)imidazo(4,5-pyrimidine-2,4,6-trithione () was synthesized by the reaction of carbon disulfide with 1,3-dimethyl-4-cyano-5-aminoimidazolidine-2-thione () which was produced by reacting trimethylsilyl cyanide with methyl isothiocyanate followed by methanolysis. An unusual reversible formation of the dimethylamine salt of is also described. 相似文献
479.
480.
A highly efficient method for the synthesis of 1-azabicyclo[x.y.0]alkane amino acid derivatives and their congeners by means of extremely regioselective cyclohydrocarbonylation (CHC) is described. The CHC reactions are catalyzed by Rh-BIPHEPHOS complex under mild conditions. These CHC reaction processes involve (i) an extremely linear-selective hydroformylation of the terminal alkene moiety of a dehydrodipeptide substrate, (ii) intramolecular condensation to form cyclic N-acyliminium key intermediate, and (iii) the second cyclization through intramolecular nucleophilic addition of a heteoatom nucleophile to the cyclic N-acyliminium moiety to afford the corresponding 1-azabicyclo[x.y.0] system. This consecutive double cyclization process proceeds with extremely high diastereoselectivity in most cases. This method has been successfully applied to the syntheses of 1-azabicyclo[4.4.0], -[5.4.0], and -[4.3.0] systems. The mechanisms of the reactions and the rationale for the observed extremely high diastereoselectivity are presented. This Rh-catalyzed CHC process would serve as a highly efficient and versatile method for the syntheses of a variety of conformationally restrained dipeptides, peptidomimetics, alkaloids, and other biologically active natural or unnatural products. 相似文献