全文获取类型
收费全文 | 118篇 |
免费 | 3篇 |
专业分类
化学 | 86篇 |
晶体学 | 1篇 |
力学 | 3篇 |
数学 | 24篇 |
物理学 | 7篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 4篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 2篇 |
2014年 | 4篇 |
2013年 | 10篇 |
2012年 | 6篇 |
2011年 | 7篇 |
2010年 | 12篇 |
2009年 | 8篇 |
2008年 | 4篇 |
2007年 | 12篇 |
2006年 | 6篇 |
2005年 | 5篇 |
2004年 | 7篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2000年 | 2篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1994年 | 2篇 |
1989年 | 2篇 |
1987年 | 3篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有121条查询结果,搜索用时 15 毫秒
1.
Vicky Mak 《Operations Research Letters》2007,35(1):36-44
This paper, using the Unconstrained Shape Matrix Optimization Problem as a test bed, we investigate various aspects of variable aggregation and disaggregation for a class of integer programs that contains binary expansion. We present theoretical and numerical results, and propose an iterative algorithm for exact solutions. 相似文献
2.
Yolande MespliÉ Michel Bergon Jean-Pierre Calmon 《Journal of heterocyclic chemistry》1984,21(4):985-993
The alkaline hydrolysis of propargyl 3-chlorocarbanilates was investigated kinetically using uv spectropotometry. The cyclization to 4-methoylene-2-oxazolisinones proceeds via the numcleophilic attack of the substrate anion concomitantly with that of the hydroxide ion on the triple bond. The nucleophilic attack leads directly to the heterocycle whereas the hydroxide ion attack gives rise to a ketocarbamate which is then cyclized to the oxazolidione. 相似文献
3.
Victor A.?ZammitEmail author Nigel T.?Price Vicky N.?Jackson Byun-Sung?Park 《Monatshefte für Chemie / Chemical Monthly》2005,136(8):1299-1309
Summary. Carnitine acyltransferases catalyse equilibria between acyl-CoA esters and the respective acylcarnitines. Therefore, they act not only as pathway enzymes, but also as modulators of acyl-CoA concentrations within individual sub-cellular compartments. Because acyl-CoA esters are potent biologically active metabolites, carnitine acyltransferase activities are potentially able to affect a diverse range of physiological processes, ranging from insulin secretion, to appetite control, and insulin sensitivity of tissues. The distinctive subcellular distributions of the different types of carnitine acyltransferases also enables them to participate in the transfer of acyl moieties across intracellular membranes, and of particular acylcarnitine esters across the plasma membrane and into the plasma. Pharmacological strategies that make use of these properties to improve cell function are discussed. 相似文献
4.
5.
Manuela F. Frasco Vicky Vamvakaki Nikos Chaniotakis 《Journal of nanoparticle research》2010,12(4):1449-1458
In this study, we report on a novel hybrid structure for the direct sensing of metal ions based on the use of CdSe quantum
dots functionalized with tetrapyridyl-substituted porphyrin, a cation-selective carrier. It is shown that the porphyrin ion
carrier coordinates to Cd atoms of the CdSe quantum dots through the Lewis basic pyridyl groups. The porphyrin-quantum dot
ligation allows for the direct communication between the porphyrin and the underlying CdSe quantum structure. The quantum
yield of CdSe is maintained despite the robust capping generated when the unmetallated porphyrins coordinate onto the quantum
dots. Upon coordination with zinc ions, this porphyrin capping is shown to strongly contribute to the increase in the fluorescence
efficiency of CdSe, via an activating interaction with the quantum dots surface. The results provide the grounds for the development
of highly sensitive and selective nano-optode sensing systems. 相似文献
6.
7.
Colette Lebrun Dr. Matthieu Starck Vicky Gathu Yves Chenavier Dr. Pascale Delangle 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(50):16566-16573
Peptides are interesting tools to rationalize uranyl–protein interactions, which are relevant to uranium toxicity in vivo. Structured cyclic peptide scaffolds were chosen as promising candidates to coordinate uranyl thanks to four amino acid side chains pre‐oriented towards the dioxo cation equatorial plane. The binding of uranyl by a series of decapeptides has been investigated with complementary analytical and spectroscopic methods to determine the key parameters for the formation of stable uranyl–peptide complexes. The molar ellipticity of the uranyl complex at 195 nm is directly correlated to its stability, which demonstrates that the β‐sheet structure is optimal for high stability in the peptide series. Cyclodecapeptides with four glutamate residues exhibit the highest affinities for uranyl with log KC=8.0–8.4 and, therefore, appear as good starting points for the design of high‐affinity uranyl‐chelating peptides. 相似文献
8.
[reactions: see text] A concise synthesis of highly functionalized cyclopentane derivatives via a Brook rearrangement mediated stereoselective linchpin cyclization reaction involving tert-butyldimethylsilyl-1,3-dithianyllithium and homochiral 1,4-bis-epoxides is described. 相似文献
9.
10.
Bharathi Avula Yan‐Hong Wang Zulfiqar Ali Troy J. Smillie Vicky Filion Alain Cuerrier John T. Arnason Ikhlas A. Khan 《Biomedical chromatography : BMC》2009,23(8):865-872
An HPLC method permitting the simultaneous determination of fourteen analytes (phenylalkanoids and monoterpenoids) from the roots of Rhodiola rosea was developed. A separation was achieved within 35 min using C18 column material and a water–acetonitrile mobile phase, both containing a 0.05% phosphoric acid gradient system and a temperature of 53°C. The method was validated for linearity, repeatability, limits of detection and limits of quantification. The limits of detection and limits of quantification of 14 phenylalkanoids and monoterpenoids were found to be 0.20–1.0 and 0.5–3.5 µg/mL, respectively. The wavelengths used for quantification of phenylalkanoids and monoterpenoids with a diode array detector were 205, 220 and 251 nm. The method was used to analyze the roots of two species of Rhodiola and commercial extracts of R. rosea and provides preliminary evidence of phytochemical differences between North American and Eurasian populations of R. rosea. LC–mass spectrometry coupled with electrospray ionization (ESI) interface method is described for the identification of phenylalkanoids and monoterpenoids in various Rhodiola samples. This method involved the use of the [M + H]+, [M + NH4]+ and [M + Na]+ ions in the positive ion mode with extractive ion monitoring (EIM). Copyright © 2009 John Wiley & Sons, Ltd. 相似文献