全文获取类型
收费全文 | 133篇 |
免费 | 7篇 |
专业分类
化学 | 104篇 |
晶体学 | 7篇 |
力学 | 6篇 |
数学 | 6篇 |
物理学 | 17篇 |
出版年
2024年 | 1篇 |
2022年 | 2篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 5篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 3篇 |
2013年 | 14篇 |
2012年 | 10篇 |
2011年 | 6篇 |
2010年 | 6篇 |
2009年 | 5篇 |
2008年 | 8篇 |
2007年 | 14篇 |
2006年 | 7篇 |
2005年 | 9篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1976年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有140条查询结果,搜索用时 31 毫秒
101.
Shekhar Kumar Bijendra Kumar M. Sampath D. Sivakumar U. Kamachi Mudali R. Natarajan 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(3):797-800
Nuclear solvent extraction was traditionally performed with packed columns, pulse columns, mixer-settlers and centrifugal
extractors. However for rapid separations at micro-flow level, micro mixer-settlers were desired and in the past, few of them
were actually designed and operated in nuclear solvent extraction research. In the current era of micro-reactor and microchannel
devices, there is a renewed interest for micro-mixer-settlers for costly solvents and specialty solutes where small flow-rate
is not an issue. In this article, development of a simple but effective micro-mixer-settler for nuclear solvent extraction
is reported. The developed unit was tested with 30% TBP/n-dodecane/nitric acid system and in both the regimes of mass transfer c → d (mass transfer from continuous phase to dispersed
phase, also written as c → d) and d → c (mass transfer from dispersed phase to continuous phase, also written as d → c) nearly
100% efficiency was observed in extraction as well as stripping modes of operation. 相似文献
102.
Matam Chandrasekharaiah Appoothy Thulasi Madiajagan Bagath Duvvuri Prasanna Kumar Sunil Singh Santosh Chenniappan Palanivel Vazhakkala Lyju Jose Koratokare Thirumalachar Sampath 《Applied biochemistry and biotechnology》2012,167(1):132-141
The metagenomic approach has been used successfully to isolate novel biocatalyst gene from uncultured microorganisms. The gene encoding exo-1,4-??-glucanase avicelase was amplified from the metagenome of the Equus burchelli fecal sample and cloned. The gene was found to be of 1,007?bp of nucleotide which encodes a protein of 318 amino acids with a calculated MW of 36?kDa. The deduced amino acid sequence was homologous with cellulases belonging to the glycosyl hydrolases 6 superfamily. The expressed protein was active towards the substrates avicel and carboxymethyl cellulose, indicating that it has bifunctional cellulolytic enzyme activity. The recombinant protein showed an activity of 5.23?U with specific activity of 6.8?U?mg?1 protein with the substrate avicel, while when CMC was used, an activity of 3.0?U with a specific activity of 4.2?U?mg?1 protein was achieved. Its optimum pH was determined to be 7.0 and optimum temperature of 35°C. 相似文献
103.
This study examines the chemical composition and in?vitro anticancer activity of the essential oil from Ocimum basilicum Linn. (Lamiaceae), cultivated in the Western Ghats of South India. The chemical compositions of basil fresh leaves were identified by GC-MS: 11 components were identified. The major constituents were found to be methyl cinnamate (70.1%), linalool (17.5%), β-elemene (2.6%) and camphor (1.52%). The results revealed that this plant may belong to the methyl cinnamate and linalool chemotype. A methyl thiazol tetrazolium assay was used for in?vitro cytotoxicity screening against the human cervical cancer cell line (HeLa), human laryngeal epithelial carcinoma cell line (HEp-2) and NIH 3T3 mouse embryonic fibroblasts. The IC(50) values obtained were 90.5 and 96.3?μg?mL(-1), respectively, and the results revealed that basil oil has potent cytotoxicity. 相似文献
104.
Raghu Gunigollahalli Kempegowda Sampath Srinivasan Pandurangappa Malingappa 《Journal of Solid State Electrochemistry》2012,16(5):1953-1963
A new type of covalent bulk modified glassy carbon composite electrode has been fabricated and utilized in the simultaneous
determination of lead and cadmium ions in aqueous medium. The covalent bulk modification was achieved by the chemical reduction
of 2-hydroxybenzoic acid diazonium tetrafluroborate in the presence of hypophosphorous acid as a chemical reducing agent.
The covalent attachment of the modifier molecule was examined by studying Fourier transform infrared spectroscopy, X-ray photoelectron
spectroscopy and the surface morphology was examined by scanning electron microscopy images. The electrochemistry of modified
glassy carbon spheres was studied by its cyclic voltammetry to decipher the complexing ability of the modifier molecules towards
Pb2+ and Cd2+ ions. The developed sensor showed a linear response in the concentration range 1–10 μM with a detection limit of 0.18 and
0.20 μM for lead and cadmium, respectively. The applicability of the proposed sensor has been checked by measuring the lead
and cadmium levels quantitatively from sewage water and battery effluent samples. 相似文献
105.
A large scale synthesis of valdecoxib 1 is described. Our work features potential application of [3 + 2]-dipolar cycloaddition involving enamine and in situ–generated nitrile oxide derivatives. 相似文献
106.
Jabeena Khazir Intizar Ali Inshad Ali Khan Halmuthur Mahabalarao Sampath Kumar 《Natural product research》2015,29(8):727-734
Enzymatic acylation of verbascoside, a polyhydroxylated natural product, has been reported in this study using five different commercial lipases and taking p-nitrophenyl alkanoates as acyl donors. Out of these enzymes, the immobilised Candida antarctica lipase B was found as the enzyme of choice. Mono- and di-acylated products were formed, with mono as major product indicating high regioselective nature of such transformations. A series of acyl esters of verbascoside have been synthesised by this enzymatic transesterification methodology. The lipophilicity of the synthesised analogues was also checked. The analogues were further subjected to synergistic antifungal activity with amphotericin B (AmB) against Candida albicans. Fourfold reduction in minimum inhibitory concentration of AmB was observed with few synthesised analogues such as verbascoside 4″-octanoate (3b), verbascoside 4″-palmitate (3d) and verbascoside 4″,4′-dipalmitate (4d) at a concentration of 0.5 μg/mL. 相似文献
107.
108.
Sampath Kannan Todd Proebsting 《Journal of Algorithms in Cognition, Informatics and Logic》1998,29(2):223-237
In this article we look at the register allocation problem. In the literature this problem is frequently reduced to the general graph coloring problem and the solutions to the problem are obtained from graph coloring heuristics. Hence, no algorithm with a good performance guarantee is known. Here we show that when attention is restricted tostructured programswhich we define to be programs whose control-flow graphs are series-parallel, there is an efficient algorithm that produces a solution which is within a factor of 2 of the optimal solution. We note that even with the previous restriction the resulting coloring problem is NP-complete.We also consider how to delete a minimum number of edges from arbitrary control-flow graphs to make them series-parallel and to apply our algorithm. We show that this problem is Max SNP hard. However, we define the notion of anapproximate articulation pointand we give efficient algorithms to find approximate articulation points. We present a heuristic for the edge deletion problem based on this notion which seems to work well when the given graph is close to series-parallel. 相似文献
109.
110.
Aldoximes undergo rapid dehydration with H2SO4/ SiO2 solid support, under microwave irradiation in dry media to afford nitriles in high yields. 相似文献