全文获取类型
收费全文 | 119篇 |
免费 | 20篇 |
专业分类
化学 | 130篇 |
晶体学 | 7篇 |
物理学 | 2篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 11篇 |
2018年 | 6篇 |
2017年 | 2篇 |
2016年 | 7篇 |
2015年 | 10篇 |
2014年 | 3篇 |
2013年 | 2篇 |
2012年 | 5篇 |
2011年 | 16篇 |
2010年 | 8篇 |
2009年 | 5篇 |
2008年 | 11篇 |
2007年 | 2篇 |
2006年 | 3篇 |
2005年 | 1篇 |
2004年 | 2篇 |
2003年 | 8篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 9篇 |
1998年 | 7篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1994年 | 1篇 |
排序方式: 共有139条查询结果,搜索用时 15 毫秒
91.
92.
C. Ragupathi S. Narayanan P. Tamizhdurai Mani Govindasamy Zeid A. ALOthman Murefah Mana AL-Anazy 《Journal of Saudi Chemical Society》2021,25(7):101275
The main aim of the paper to the synthesis of Mn (x)-doped NiCr2O4 nanoparticles by varying Mn content (x = 0.00%, 0.01%, 0.02%, and 0.03%) by microwave method for correlating the effect of NiCr2O4 on structural, optical, and magnetic properties of the materials. Understanding the optical, magnetic, and structural properties of huge reservoir factors has essential applications in various aspects of materials science. Our study is to relate the reduction of grain size of Mn content in NiCr2O4 host material. The XRD results revealed that there was an apparent decrease in the characteristic peaks of Mn in the MnNiCr2O4 nanostructure. Particularly, the peak position of (2 2 0) and (3 1 1) planes was decreased. This decrease in peak position is attributed to the creation of defects or disorders due to the Mn ions in the chromite lattice structure. This inter-site Mn cation migration is responsible for the breaking of long-range cation order and the introduction of defects at both the T-site and O-sublattices site simultaneously. 相似文献
93.
Halogen Bonding Controls the Regioselectivity of the Deiodination of Thyroid Hormones and their Sulfate Analogues 下载免费PDF全文
Dr. Debasish Manna Santanu Mondal Prof. Dr. Govindasamy Mugesh 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(6):2409-2416
The type 1 iodothyronine deiodinase (1D‐1) in liver and kidney converts the L ‐thyroxine ( T4 ), a prohormone, by outer‐ring (5′) deiodination to biologically active 3,3′,5‐triiodothyronine ( T3 ) or by inner‐ring (5) deiodination to inactive 3,3′,5′‐triiodothronine ( rT3 ). Sulfate conjugation is an important step in the irreversible inactivation of thyroid hormones. While sulfate conjugation of the phenolic hydroxyl group stimulates the 5‐deiodination of T4 and T3 , it blocks the 5′‐deiodination of T4 . We show that thyroxine sulfate ( T4S ) undergoes faster deiodination as compared to the parent thyroid hormone T4 by synthetic selenium compounds. It is also shown that ID‐3 mimics, which are remarkably selective to the inner‐ring deiodination of T4 and T3 , changes the selectivity completely when T4S is used as a substrate. From the theoretical investigations, it is observed that the strength of halogen bonding increases upon sulfate conjugation, which leads to a change in the regioselectivity of ID‐3 mimics towards the deiodination of T4S . It has been shown that these mimics perform both the 5′‐ and 5‐ring deiodinations by an identical mechanism. 相似文献
94.
Govindasamy Gurumoorthy 《Phosphorus, sulfur, and silicon and the related elements》2017,192(3):330-337
Bis(N-(pyrrol-2-ylmethyl)-N-isopropyldithiocarbamato-S,S′)nickel(II) (1) and (N-(pyrrol-2-ylmethyl)-N-isopropyldithiocarbamato-S,S′)(thiocyanato-N)(triphenylphosphine)nickel(II) (2) have been prepared and characterized by elemental analysis, IR, 1H, and13C NMR and UV-visible absorption spectra. In addition, the structures of 2 and (N-(pyrrol-2-ylmethyl)-N-butyldithiocarbamato-S,S′)(thiocyanato-N)(triphenylphosphine)nickel(II) (3) have been elucidated by X-ray crystallography. UV-vis spectral data are consistent with the formation of square planar complexes. The crystal structures of 2 and 3 reveal S2NP square-planar configuration around the Ni atom. A rare C–H···Ni short contact interaction was observed in complex 3 involving ortho-hydrogen atom of one of the phenyl ring of the triphenylphosphine. DFT calculations on complexes 2 and 3are in close agreement with the crystallographic results. The energy gap between HOMO and LUMO for 2 and 3 is 2.7167 and 2.6936 eV, respectively. Molecular electrostatic potential analysis of 2 and 3 support the partial double character of thioureide C–N bond. 相似文献
95.
96.
97.
98.
The effect of steric and electronic environments around the sulfur and nitrogen atoms and the role of nonbonded S...O/N interactions on the cyclization reactions of amide substituted benzene sulfenic acids are described. The reaction profiles and the role of different substituents on the cyclization are investigated in detail by theoretical calculations. It is shown that the synthetic thiols having ortho-amide substituents may serve as good models for the enforced proximity of the amide and cysteine thiol groups at the active site of protein tyrosine phosphatase 1B (PTP1B). However, some of the sulfenic acids derived from such models do not effectively mimic the cyclization of protein sulfenic acids. This is mainly due to the requirement of very high energy for breaking the S-O bond to form a planar five-membered ring of isothiazolidinone. It is shown that the sulfenic acid having two substituents-an amide moiety and a heterocyclic group-in the ortho-positions undergoes a rapid cyclization reaction to produce the corresponding sulfenyl amide species. These studies reveal that the introduction of a substituent at the 6-position of the benzene ring enhances the cyclization process not only by facilitating a closer approach of the -OH group and the backbone -NH moiety but also by increasing the electrophilicity of the sulfur atom in the sulfenic acid. 相似文献
99.
Flow‐Through Synthesis on Teflon‐Patterned Paper To Produce Peptide Arrays for Cell‐Based Assays 下载免费PDF全文
Dr. Frédérique Deiss Wadim L. Matochko Natasha Govindasamy Edith Y. Lin Dr. Ratmir Derda 《Angewandte Chemie (International ed. in English)》2014,53(25):6374-6377
A simple method is described for the patterned deposition of Teflon on paper to create an integrated platform for parallel organic synthesis and cell‐based assays. Solvent‐repelling barriers made of Teflon‐impregnated paper confine organic solvents to specific zones of the patterned array and allow for 96 parallel flow‐through syntheses on paper. The confinement and flow‐through mixing significantly improves the peptide yield and simplifies the automation of this synthesis. The synthesis of 100 peptides ranging from 7 to 14 amino acids in length gave over 60 % purity for the majority of the peptides (>95 % yield per coupling/deprotection cycle). The resulting peptide arrays were used in cell‐based screening to identify 14 potent bioactive peptides that support the adhesion or proliferation of breast cancer cells in a 3D environment. In the future, this technology could be used for the screening of more complex phenotypic responses, such as cell migration or differentiation. 相似文献
100.
Govindasamy Balasubramani Paramasivam Deepak Rajamani Sowmiya Rajendiran Ramkumar 《Natural product research》2015,29(10):958-960
This study pertains to the phytochemical components and the biological properties of the weed, Antigonon leptopus Hook. & Arn. (AUT/PUS/064). Phytochemical screening of methanolic leaf extract of A. leptopus revealed the presence of saponin, phenolic compounds, tannins, flavonoids, alkaloids, fixed oils and amino acids. Accordingly, 12 phytochemical components were analysed and characterised by GC–MS. Antibacterial activity was evaluated against fish and clinical pathogens. Fish pathogens, Providencia vermicola (MTCC 5578) and Aeromonas hydrophila (MTCC 646) were more sensitive to the methanolic leaf extract than clinical pathogens. A useful information was obtained from the phytochemistry of A. leptopus leaves, which would pave way to further applications to treat fish diseases and for utility in the pharmaceutical field. 相似文献