全文获取类型
收费全文 | 676篇 |
免费 | 13篇 |
国内免费 | 2篇 |
专业分类
化学 | 465篇 |
晶体学 | 9篇 |
力学 | 16篇 |
数学 | 130篇 |
物理学 | 71篇 |
出版年
2023年 | 2篇 |
2021年 | 5篇 |
2020年 | 8篇 |
2019年 | 6篇 |
2018年 | 3篇 |
2017年 | 8篇 |
2016年 | 11篇 |
2015年 | 21篇 |
2014年 | 15篇 |
2013年 | 47篇 |
2012年 | 35篇 |
2011年 | 34篇 |
2010年 | 18篇 |
2009年 | 21篇 |
2008年 | 27篇 |
2007年 | 41篇 |
2006年 | 30篇 |
2005年 | 24篇 |
2004年 | 20篇 |
2003年 | 31篇 |
2002年 | 23篇 |
2001年 | 8篇 |
2000年 | 14篇 |
1999年 | 13篇 |
1998年 | 6篇 |
1997年 | 10篇 |
1996年 | 10篇 |
1995年 | 15篇 |
1994年 | 9篇 |
1993年 | 10篇 |
1992年 | 14篇 |
1991年 | 7篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 6篇 |
1987年 | 8篇 |
1985年 | 9篇 |
1984年 | 6篇 |
1983年 | 2篇 |
1982年 | 9篇 |
1981年 | 16篇 |
1980年 | 10篇 |
1979年 | 8篇 |
1978年 | 12篇 |
1977年 | 11篇 |
1976年 | 9篇 |
1975年 | 12篇 |
1974年 | 4篇 |
1973年 | 6篇 |
1966年 | 3篇 |
排序方式: 共有691条查询结果,搜索用时 15 毫秒
81.
82.
83.
(±) Sarkomycin ethyl ester has been prepared in four steps from ethyl acrylate. 相似文献
84.
Jacques Dubac Pierre Mazerolles Monique Joly 《Journal of organometallic chemistry》1977,128(2):C18-C20
Stereospecific synthesis of geometric isomers of 1,2-dimethyl-1-phenylsilacyclopentane is described. We demonstrate that brominolysis of the arylsilicon bond occurs with predominant inversion of configuration at the silicon atom of the silacyclopentane ring. 相似文献
85.
Jacques Dubac Pierre Mazerolles Monique Joly 《Journal of organometallic chemistry》1977,128(2):C21-C24
The stereoselective alcoholysis of 1,2-dimethyl-1-chlorosilacyclopentane and the catalytic alcoholysis of 1,2-dimethylsilacyclopentane are described. 相似文献
86.
Jean Pierre Majoral Monique Revel Raymond Kraemer Hlne Germa Jacques Navech 《Journal of heterocyclic chemistry》1977,14(5):749-755
The reaction of phosphodi- or trihydrazides with orthoesters affords mainly 2,3,4,5-tetrahydro-1,2,4,5,3-tetrazaphosphorines and sometimes 4-amino-1,2,4,3-triazaphospholidines. These 1,2,4,5,3-tetrazaphosphorines present a prototropy which explains different pathways of the reaction of these derivatives with formaldehyde or acetone, The structure of all heterocycles which were obtained was established by nmr spectra. 相似文献
87.
88.
Monique Combescot 《Applied Physics A: Materials Science & Processing》1991,53(6):547-551
We show that the exciton optical Stark effect is basically a dressed-exciton effect: excitons are dressed by the electromagnetic field in a way similar to the way atoms are dressed. The situation appears, however, much richer in semiconductor than in atomic physics due to both the complexity of the band structure and the Coulomb interaction between excitons. We show that the dressed-exciton effect can appear as either a blue or a red shift of the exciton line as well as a splitting of exciton levels, with an interesting dimensional effect in the absorption strength. We also relate the dressed-exciton to the polariton effect. 相似文献
89.
V.K. Kansal S. Funakoshi P. Mangeney B. Gillet E. Guittet J.-Y. Lallemand P. Potier 《Tetrahedron》1985,41(22):5107-5120
Reaction of 9-hydroxypyrido[4,3-b] carbazole derivatives under oxidative conditions (biochemical : HRP/H2O2, chemical : Cu2Cl2/Pyridine/O2) has been found to furnish regio-and stereo-selectively a ketalic linkage at the 10-position of this type of compound. Detailed structure elucidation of the products has been given. The regio- and stereo-specificity of the reaction has been demonstrated to be due to π-π stacking between the ribonucleosidic base and the 9-hydroxypyridocarbazole nucleus. Acid Catalysed isomerisation of to has also been studied in detail. In the light of these results, it is proposed that besides the “classical” intercalation into DNA, this type of compound can also react with RNA. This reactivity could explain, at least partially, the pharmacological (antitumour) activity of these compounds and should lead to a promising field of research in molecular biology. 相似文献
90.