全文获取类型
收费全文 | 115篇 |
免费 | 1篇 |
专业分类
化学 | 70篇 |
晶体学 | 2篇 |
力学 | 1篇 |
数学 | 9篇 |
物理学 | 34篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 10篇 |
2019年 | 3篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 5篇 |
2015年 | 3篇 |
2014年 | 6篇 |
2013年 | 22篇 |
2012年 | 7篇 |
2011年 | 6篇 |
2010年 | 3篇 |
2009年 | 2篇 |
2008年 | 3篇 |
2007年 | 3篇 |
2006年 | 2篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 8篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1995年 | 1篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1988年 | 1篇 |
1977年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有116条查询结果,搜索用时 15 毫秒
1.
Donia A. M. El-Boraey H. A. El-Samalehy M. F. 《Journal of Thermal Analysis and Calorimetry》2003,73(3):987-1000
Manganese and iron complexes of Schiff bases derived from 6-formylkhellin were prepared and characterized. Complexes of o-phenylenediamine derivative (ligand (I)) are monomeric or dimeric whereas those of p-phenylenediamine derivative (ligand (II)) are polymeric. The complexes obtained are characterized by a lower magnetic moment
values. The complexes also have different solvent of crystallization with different nature of interaction. The thermal behaviour
of the ligands and their metal complexes was investigated by means of DTA, TG, IR and X-ray diffraction spectroscopy. Ligand
(I) shows different thermal behaviour from that of ligands (II) and (III). The complexes of ligand (II) give abnormal oxides
as a final product during their thermal decomposition.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
2.
The atomic superposition and electron delocalization molecular orbital (ASED-MO) theory was used to calculate structures and relative stabilities of metformin-metal complexes. The relative stabilities and decomposition pathways were discussed in terms of bond order, binding energy and the nature of charge on the central metal atom. The electronic transitions and their energy gaps were also studied. The optimization of the structures shows that the most stable state is distorted from planarity for CoII and NiII complexes. 相似文献
3.
4.
5.
A. A. F. Wasfy M. S. Amine M. M. H. Arief S. G. Donia A. A. Aly 《Phosphorus, sulfur, and silicon and the related elements》2013,188(5):1359-1368
4-(5,5-Dioxodibenzothiophen-2-yl)-4-oxo-2-butenoic acid ( 1 ) was condensed with compounds containing active methylene groups under Michael reaction conditions to form the Michael adducts 2a-c , 3a-c , and 4a-b . The behavior of Michael adduct towards the action of hydrazine hydrate was investigated. The compounds were tested for biological properties. 相似文献
6.
7.
Ahmed M. Donia Asem A. Atia Hassnaa M. Abd El-Latif 《Journal of Dispersion Science and Technology》2014,35(3):380-389
Cellulose was modified via chlorination using phosphorous oxychloride followed by functionalization with amine and thiol moieties. The obtained modified cellulose samples were investigated by means of FTIR, TGA, TEM, and nitrogen-adsorption surface area (BET). The BET measurements showed a remarkable increase in the surface area of Cell-N-S (477.7 m2/g) and Cell-N (706 m2/g). The resins gave an uptake capacities of 38 and 7.2mmol/g for Cell-N-S and Cell-N, respectively toward Hg(II) from its solutions. These values are considered much better compared with other reported resins. Regeneration of the resins was achieved effectively using acidified thiourea. 相似文献
8.
Dr. Viktor Pfeifer Marie Certiat Dr. Donia Bouzouita Dr. Alberto Palazzolo Sébastien Garcia-Argote Elodie Marcon David-Alexandre Buisson Dr. Philippe Lesot Prof. Laurent Maron Dr. Bruno Chaudret Dr. Simon Tricard Dr. Iker del Rosal Prof. Romuald Poteau Dr. Sophie Feuillastre Dr. Grégory Pieters 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(22):4988-4996
Ruthenium nanocatalysis can provide effective deuteration and tritiation of oxazole, imidazole, triazole and carbazole substructures in complex molecules using D2 or T2 gas as isotopic sources. Depending on the substructure considered, this approach does not only represent a significant step forward in practice, with notably higher isotope uptakes, a broader substrate scope and a higher solvent applicability compared to existing procedures, but also the unique way to label important heterocycles using hydrogen isotope exchange. In terms of applications, the high incorporation of deuterium atoms, allows the synthesis of internal standards for LC-MS quantification. Moreover, the efficacy of the catalyst permits, even under subatmospheric pressure of T2 gas, the preparation of complex radiolabeled drugs owning high molar activities. From a fundamental point of view, a detailed DFT-based mechanistic study identifying undisclosed key intermediates, allowed a deeper understanding of C−H (and N−H) activation processes occurring at the surface of metallic nanoclusters. 相似文献
9.
Ozlem Yazici M. Reyhan Moroglu Husnu Cankurtaran Ozlem Cankurtaran Ferdane Karaman 《Mikrochimica acta》2008,160(4):441-445
The composites of graphite with Ardel?D-100 which is a trademark of a polyester of bisphenol-A with terephthalic and isophthalic acid were used as a sensing material
in a conductometric vapor sensor. The magnitudes of responses are increased in the order of benzene, isobutyl acetate, isoamyl
acetate, ethyl benzene and chloro benzene. This suggests that Ardel?D-100 can be used as a sensing material for chlorobenzene, ethyl benzene and isoamyl acetate. On the other hand, specific
retention volumes of the sensed vapors on Ardel?D-100 coated on graphite were determined by inverse gas chromatography at temperatures between 200 and 260 °C. The distribution
coefficient, K
s of the vapors between stationary and mobile phases in the column was obtained. It was revealed for the first time that the
logarithm of K
s of the solvents varies almost linearly with their responses based on conductometric resistance of the sensing polymer composite.
Subsequently, the study suggests that gas chromatographic retention data can be used in prediction of the conductometric responses
of a polymeric sensor to vapors.
Correspondence: Ferdane Karaman, Department of Chemistry, Yildiz Technical University, 34220 Istanbul-Esenler, Turkey 相似文献
10.
Karaman R 《Journal of computer-aided molecular design》2010,24(12):961-970
DFT calculation results for intramolecular proton transfer reactions in Kirby’s enzyme models 1–7 reveal that the reaction rate is quite responsive to geometric disposition, especially to distance between the two reactive
centers, r
GM, and the angle of attack, α (the hydrogen bonding angle). Hence, the study on the systems reported herein could provide a
good basis for designing aza nucleoside prodrug systems that are less hydrophilic than their parental drugs and can be used,
in different dosage forms, to release the parent drug in a controlled manner. For example, based on the calculated log EM,
the cleavage process for prodrug 1ProD is predicted to be about 1010 times faster than that for prodrug 7ProD and about 104 times faster than prodrug 3ProD: rate
1ProD
> rate
3ProD
> rate
7ProD
. Hence, the rate by which the prodrug releases the aza nucleoside drug can be determined according to the structural features
of the linker (Kirby’s enzyme model). 相似文献