全文获取类型
收费全文 | 100篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
化学 | 83篇 |
晶体学 | 1篇 |
力学 | 2篇 |
物理学 | 16篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2017年 | 2篇 |
2016年 | 5篇 |
2015年 | 1篇 |
2013年 | 4篇 |
2012年 | 6篇 |
2011年 | 7篇 |
2010年 | 5篇 |
2009年 | 3篇 |
2008年 | 8篇 |
2007年 | 8篇 |
2006年 | 8篇 |
2005年 | 7篇 |
2004年 | 1篇 |
2003年 | 2篇 |
2002年 | 12篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1985年 | 3篇 |
1978年 | 1篇 |
排序方式: 共有102条查询结果,搜索用时 562 毫秒
31.
Rawal RK Solomon VR Prabhakar YS Katti SB De Clercq E 《Combinatorial chemistry & high throughput screening》2005,8(5):439-443
Selected 4-thiazolidinone have been synthesized and tested as anti-HIV activity. The results of the in vitro tests showed that one of the compounds, 5, inhibited the enzyme at 0.204 microM concentration with minimal toxicity to MT-4 cell. Furthermore, the QSAR studies indicated the role of PMIZ, Ovality and Total energy content of the compounds in rationalizing the activity. 相似文献
32.
The structure of 1,3-dehydro-5-adamantyl cation and its isoelectronic boron analogue 1,3-dehydro-5-boraadamantane as well as some related adamantane systems, hitherto unknown as persistent long-lived species, were investigated by using the density functional theory (DFT) method. (13)C and (11)B NMR chemical shifts of the compounds were also calculated using the IGLO method. Stabilization of the systems due to homoconjugation is discussed. 相似文献
33.
GK Johri Akhilesh Tiwari Saumya Saxena Rajesh Sharma Kuldeep Srivastava Manoj Johri 《Pramana》2002,58(3):563-567
Calculations for the relative width (Δω/ω0) as a function of refractive index and relative radius of the photonic band gap for the fcc closed packed 3-D dielectric
microstructure are reported and comparison of experimental observations and theoretical predictions are given. This work is
useful for the understanding of photonic crystals and occurrence of the photonic band gap. 相似文献
34.
We report the first examples of hydrogen-bond-promoted acceleration of hetero-Diels-Alder reactions and the use of such catalysis for the hetero-Diels-Alder reactions of simple, unactivated ketones. Several spiro-fused dihydropyans were synthesized in good yields using this procedure. This activation protocol represents an attractive and operationally simple alternative to conventional, Lewis acid catalysis. 相似文献
35.
The facile lithiation of thioacetals has led to their extensive development as Umpolung reagents of great utility in general organic synthesis.1 In contrast, the corresponding monothioacetals, such as α-alkoxysulfides, have received little attention for similar synthetic purposes. The most investigated reagent of this class has been the α-lithio derivative (2) of α-methoxy-thioanisole (methoxymethylphenylthioether, 1), which we will henceforth refer to as LMT. The first reported use of LMT was in 1975 by Trost, who showed that it added cleanly to the carbonyl of several bicyclic lactones.2 Subsequent studies of LMT have been limited to one example of its addition to a lithiated tosylhydrazone to give eventually an enol ether,3 and several cases of its addition to ketone carbonyls as the first step of an unsaturated aldehyde synthesis.4,5 We now report a new, convenient and non-hazardous synthesis of α-methoxythioanisole (1), as well as a broad overview of the reactions of its lithio derivative LMT (2) with some representative alkyl halides, epoxides, aldehydes, nitriles, amides, and an ester and an acid chloride. 相似文献
36.
A. Rawal X.‐W. Fang K. Urman D. Iverson J. U. Otaigbe K. Schmidt‐Rohr 《Journal of Polymer Science.Polymer Physics》2008,46(9):857-860
The effect of tin fluorophosphate‐glass (Pglass) nanoparticles on the polyamide‐6 (PA6) matrix in Pglass/PA6 hybrids has been investigated by 13C solid‐state nuclear magnetic resonance (NMR). The crystallinity determined by direct‐polarization 13C NMR combined with longitudinal relaxation‐time (T1C) filtering varied between 31 and 44%. T1C‐filtered 13C spectra with cross polarization clearly showed resonances of both the α‐ and γ‐crystalline phases of PA6, typically at ratios near 45:55, while the similarly processed neat polymer contained only the α‐phase. This suggests that the Pglass promotes the growth of the γ‐crystalline phase. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 857–860, 2008 相似文献
37.
Given the prevalence of the indole nucleus in biologically active compounds, the direct C3-functionalization of 2,3-disubstituted indoles represents an important problem. Described is a general, high-yielding method for the palladium-catalyzed beta-allylation of carba- and heterocycle fused indoles, including complex natural product substrates. 相似文献
38.
Julius R. Reyes Prof. Dr. Viresh H. Rawal 《Angewandte Chemie (International ed. in English)》2016,55(9):3077-3080
A method is presented for the direct transformation of a ketone to the corresponding reduced alkyl chloride or bromide. The process involves the reaction of a ketone trityl hydrazone with tBuOCl to give a diazene which readily collapses to the α‐chlorocarbinyl radical, reduction of which by a hydrogen atom source gives the alkyl chloride product. The use of N‐bromosuccinimide provides the corresponding alkyl bromide. This unique transformation provides a reductive halogenation that complements Barton's redox‐neutral vinyl halide synthesis. 相似文献
39.
Described is an efficient synthesis of silyl-substituted salen ligands, used for the preparation of enantioselective catalysts. The salicylaldehyde precursors are synthesized from the silyl ethers of 2,6-dibromophenols via a one-pot double lithium halogen exchanges, to induce an intramolecular retro-Brook rearrangement and allow introduction of the aldehyde group. Condensation of the salicylaldehyde products with a chiral diamine affords the silyl-substituted salen ligands in high yields. The use of other electrophiles allows easy access to silyl-substituted phenolic esters, ketones, and boronic acids. 相似文献
40.