全文获取类型
收费全文 | 95篇 |
免费 | 0篇 |
专业分类
化学 | 74篇 |
晶体学 | 18篇 |
物理学 | 3篇 |
出版年
2013年 | 10篇 |
2011年 | 2篇 |
2010年 | 1篇 |
2006年 | 1篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 3篇 |
1985年 | 9篇 |
1984年 | 4篇 |
1982年 | 2篇 |
1981年 | 6篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 8篇 |
1972年 | 4篇 |
排序方式: 共有95条查询结果,搜索用时 0 毫秒
31.
32.
N-Sulfinyl p-toluenesulfonamide (1) reacted with triaryl- and diarylmethanols to give predominantly N- substiuted sulfonamides and SO2 presumably via carbonium ion intermediates. When carbonium ion forming alchols, such as t-BuOH and Ph2C(Me)OH, were used the predominant products were alkenes and p- toluenesulfonamide. Allytic alcohols afforded N- substiuted sulfonamides along with dienes andp-toluenesulfonamide. Alcohols which could not predictably give relatively stable intermediate carbonium ions, gave either dialkyl sulfites or dialkyl eithers, along with p-toluenesulfonamide. In one case, namely with 9-phenylfluorenol the 1:1 adduct with 1 (an amidosulfite) was isolated. A mechanism for the reactions is proposed. 相似文献
33.
Stereoselective reduction of 1,3-bishomocubanone acetate followed by mesylation leads to an epimeric mixture of mesylates . Base induced homoketonization of the anti-epimer affords tetracyclo[5.3.0.02,5 O4,8]decenone . 相似文献
34.
35.
Theodorus J. G. Damen Binne Zwanenburg 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):319-320
The synthesis of several α-oxo sulfines is discribed. Various α-oxo sulfines can be isolated as such. The Diels-Alder reaction of these sulfines with 1,3-dienes can be catalyzed by Lewis acids. 相似文献
36.
37.
J. M. M. Smits V. Parthasarathi Paul T. Beurskens L. Thus E. Mangnus B. Zwanenburg 《Journal of chemical crystallography》1986,16(3):339-345
The structure of the title compound (perhydroisoindole) was determined by X-rays, using CuK radiation (graphite-crystal monochromator, =1.54184 Å):T=290 K, C16H17NO4,M
r
=287.31, orthorhombic, space groupPbcn,a=18.732(1),b=10.663(1),c=14.074(1) 0A,V
c
=2811.2 Å3,Z=8,D
x
=1.361 Mg m–3 and (CuK)=8.19 cm–1. The final conventionalR-factor=0.036, (R
w
=0.046) for 1951 unique reflections and 241 variables. The structure was solved usingMultan. The six-membered ring of the molecule is in the chair configuration. The molecules are connected by hydrogen bonds. 相似文献
38.
39.
Reactions of α,β-epoxy diazomethyl ketones 1a-1with activated copper powder or copper(II) sulfate in methanol (or ethanol) lead to 1,1 - dialkoxy - but - 3 - ene - 2 - ones 2 (or 3) in good yields. This process of oxygen transfer proceeds via initially generated keto-carbenoids which react intramolecularly with the epoxide function to give bicyclic intermediates 10. Release of strain and subsequent ring opening produces but - 3 - ene - 1,2 - diones which acetalise to give the ultimate reaction products 2 (or 3). With copper as catalyst byproducts were isolated, viz 1,1 - dialkoxy - 4 - hydroxy - butane - 2 - ones (4 and 5), and indanone derivative 6. An explanation for these side reactions has been given. 相似文献
40.