全文获取类型
收费全文 | 100篇 |
免费 | 0篇 |
专业分类
化学 | 55篇 |
力学 | 11篇 |
数学 | 17篇 |
物理学 | 17篇 |
出版年
2022年 | 1篇 |
2020年 | 1篇 |
2018年 | 1篇 |
2016年 | 2篇 |
2014年 | 3篇 |
2013年 | 3篇 |
2011年 | 2篇 |
2010年 | 5篇 |
2009年 | 3篇 |
2008年 | 4篇 |
2006年 | 6篇 |
2005年 | 5篇 |
2004年 | 4篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 5篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1985年 | 1篇 |
1983年 | 5篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1976年 | 2篇 |
1973年 | 4篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1915年 | 2篇 |
排序方式: 共有100条查询结果,搜索用时 0 毫秒
1.
[(?) (R)-1,2-bis (Diphenylphosphino)-1-phenylethane]nickel (II) chloride was found to catalyze the asymmetric alkylation of some chiral and achiral allylic alcohols with Grignard reagents, leading to the formation of optically active olefins. Enantiomer discrimination of the substrate takes place in the alkylation of chiral allylic alcohols. 相似文献
2.
Piero Pino Felix Oldani Giambattista Consiglio 《Journal of organometallic chemistry》1983,250(1):491-497
In the hydroformylation of ethylene with approximately equimolar H2/D2 mixtures and Rh4(CO)12 or Co2(CO)8 as the catalyst precursor about 50% of propionaldehyde-d1 was formed. The propionaldehyde-d0/d2 ratio was ~ 3 for rhodium and ~ 2.6 for the cobalt catalyst. On the basis of the results and assuming that there is no rapid M(H)2/M(D)2 scrambling, activation of hydrogen through M(H)2 or M(H)2(olefin) complexes can be excluded. 相似文献
3.
In spite of the higher reactivity of styrene with respect to ethene for the alternating copolymerization with carbon monoxide, catalyzed by chiral (dihydrooxazole)(phosphino)palladium complexes, ethene is preferentially (and randomly) enchained in terpolymerization experiments; enantioface selection for styrene is comparably high in both copolymerization and terpolymerization processes. 相似文献
4.
Anil Kumar PG Pregosin PS Schmid TM Consiglio G 《Magnetic resonance in chemistry : MRC》2004,42(9):795-800
Three new salts of Rh(I), [Rh(1,5-COD)(Biphemp)]X, Biphemp = (6,6'-dimethylbiphenyl-2,2'-diyl)bis(diphenylphosphine), X = BF4-, 2a, PF6-, 2b, and CF3SO3-, 2c, were prepared and studied using PGSE diffusion, 1H-19F HOESY and inverse 103Rh (amongst other) NMR methods. Although the immediate coordination sphere of the cation does not sense the change in the anion, the PGSE diffusion and 1H-19F HOESY data suggest that, in addition to some ion pairing, each of the anions in 2 demonstrates selectivity in its approach towards the cation. 相似文献
5.
Dr. Giambattista Testolin Dr. Jana Richter Antje Ritter Dr. Hans Prochnow Prof. Dr. Jesko Köhnke Prof. Dr. Mark Brönstrup 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(54):e202201297
The rise of antibiotic resistance causes a serious health care problem, and its counterfeit demands novel, innovative concepts. The combination of photopharmacology, enabling a light-controlled reversible modulation of drug activity, with antibiotic drug design has led to first photoswitchable antibiotic compounds derived from established scaffolds. In this study, we converted cystobactamids, gyrase-inhibiting natural products with an oligoaryl scaffold and highly potent antibacterial activities, into photoswitchable agents by inserting azobenzene in the N-terminal part and/or an acylhydrazone moiety near the C-terminus, yielding twenty analogs that contain mono- as well as double-switches. Antibiotic and gyrase inhibition properties could be modulated 3.4-fold and 5-fold by light, respectively. Notably, the sensitivity of photoswitchable cystobactamids towards two known resistance factors, the peptidase AlbD and the scavenger protein AlbA, was light-dependent. While irradiation of an analog with an N-terminal azobenzene with 365 nm light led to less degradation by AlbD, the AlbA-mediated inactivation was induced. This provides a proof-of-principle that resistance towards photoswitchable antibiotics can be optically controlled. 相似文献
6.
7.
8.
9.
10.
Achiral and chiral cationic palladium catalysts, modified with atropisomeric P?N ligands with different steric and electronic properties, can efficiently produce poly(styrene‐alt‐CO) with essentially complete regioregularity and variable tacticity, depending on the ligand geometry; the electronic effect on catalytic activity depends on the geometry of the ligand. 相似文献