全文获取类型
收费全文 | 121篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
化学 | 105篇 |
力学 | 3篇 |
数学 | 4篇 |
物理学 | 14篇 |
出版年
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 3篇 |
2014年 | 7篇 |
2013年 | 14篇 |
2012年 | 1篇 |
2011年 | 6篇 |
2010年 | 3篇 |
2009年 | 6篇 |
2008年 | 8篇 |
2007年 | 6篇 |
2006年 | 3篇 |
2005年 | 9篇 |
2004年 | 2篇 |
2003年 | 4篇 |
2002年 | 5篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1992年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1970年 | 2篇 |
1969年 | 1篇 |
1967年 | 3篇 |
1965年 | 2篇 |
排序方式: 共有126条查询结果,搜索用时 31 毫秒
11.
Svitlana V. Shishkina Igor V. Ukrainets Olga V. Vashchenko Natali I. Voloshchuk Pavlo S. Bondarenko Lidiya A. Petrushova Galina Sim 《Acta Crystallographica. Section C, Structural Chemistry》2020,76(1):69-74
The title benzothiazine‐3‐carboxamide, C17H16N2O4S, crystallized in two enantiomorphic crystal forms with the space groups P32 and P31 despite the absence of a classic stereogenic atom. The molecular structures are mirror images of each other. Only one sulfonyl O atom takes part in intramolecular hydrogen bonding as a proton acceptor and this atom is different in the two enantiomorphic structures. As a result, the S atom becomes a pseudo‐stereogenic centre. This fact is worth taking into account due to the different biological activities of the enantiomorphic forms. One form possesses a high analgesic activity, while the other form revealed a high anti‐inflammatory activity. 相似文献
12.
Pinko P. I. Terakh E. I. Gorokh E. A. Nikulina V. V. Prosenko A. E. Grigor'ev I. A. 《Russian Journal of Applied Chemistry》2002,75(10):1660-1664
Unsymmetrical sulfides were prepared by reactions of -(3,5-di-tert-butyl-4-hydroxyphenyl)alkanethiols with various alkyl halides, and their antioxidant activity with respect to thermal autooxidation of lard was studied in relation to their structure. 相似文献
13.
Boris A. Trofimov Boris G. Sukhov Svetlana F. Malysheva Natal’ya A. Belogorlova Anatolii P. Tantsirev Lidiya N. Parshina Ludmila A. Oparina Sergey P. Tunik Nina K. Gusarova 《Tetrahedron letters》2004,45(49):9143-9145
Secondary phosphines react readily with a vinyl ether of diacetone-d-glucose under radical initiation conditions to give, in high yield, anti-Markovnikov adducts, diorganyl{2-[3-O-(1,2:5,6-di-O-isopropylidene)-d-glucofuranosyloxy]ethyl}phosphines, which oxidize almost quantitatively upon reacting with air oxygen or elemental sulfur to form the corresponding optically active phosphine oxides or sulfides. 相似文献
14.
L. D. Nikulina L. F. Bakhturova V. S. Danilovich 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2007,1(6):656-659
We present the results of a surface microstructure and morphology study of thin films produced from volatile fluorine-containing rare-earth β-diketonate complexes and their adducts. Films 0.2–0.4 μm in thickness were synthesized in vacuum by means of thermal deposition of the parent substances at a pressure of 5 × 10?4?1 × 10?3 Pa and a deposition rate of 3 × 10?3 μm s?1 (for NaNd(FOD)4 films, the deposition rate was 8 × 10?2 μm s?1). The microstructure of films depends on the deposition conditions. The films of [NaNd(PTFA)4] and [NaNd(FOD)4] complexes and Ln(PTFA)3 · S1 adducts have an amorphous structure. The [NaNd(PTFA)4(Phen)] and Nd(PTFA)3 · S2 films are characterized by a more ordered polycrystalline structure with the grain size ranging from 0.2 to 1.5 μm. 相似文献
15.
16.
S. P. Babailov Yu. G. Kriger T. N. Martynova L. D. Nikulina 《Journal of Structural Chemistry》1990,31(3):410-412
Institute of Inorganic Chemistry, Siberian Branch, USSR Academy of Sciences. Translated from Zhurnal Strukturnoi Khimii, Vol. 31, No. 3, pp. 44–47, May–June, May–June, 1990. 相似文献
17.
Bahadur V Mishchenko L Hatton B Taylor JA Aizenberg J Krupenkin T 《Langmuir : the ACS journal of surfaces and colloids》2011,27(23):14143-14150
The prevention and control of ice accumulation has important applications in aviation, building construction, and energy conversion devices. One area of active research concerns the use of superhydrophobic surfaces for preventing ice formation. The present work develops a physics-based modeling framework to predict ice formation on cooled superhydrophobic surfaces resulting from the impact of supercooled water droplets. This modeling approach analyzes the multiple phenomena influencing ice formation on superhydrophobic surfaces through the development of submodels describing droplet impact dynamics, heat transfer, and heterogeneous ice nucleation. These models are then integrated together to achieve a comprehensive understanding of ice formation upon impact of liquid droplets at freezing conditions. The accuracy of this model is validated by its successful prediction of the experimental findings that demonstrate that superhydrophobic surfaces can fully prevent the freezing of impacting water droplets down to surface temperatures of as low as -20 to -25 °C. The model can be used to study the influence of surface morphology, surface chemistry, and fluid and thermal properties on dynamic ice formation and identify parameters critical to achieving icephobic surfaces. The framework of the present work is the first detailed modeling tool developed for the design and analysis of surfaces for various ice prevention/reduction strategies. 相似文献
18.
S. V. Sysoev L. D. Nikulina A. O. Kolontaeva M. L. Kosinova A. A. Titov V. I. Rakhlin I. P. Tsyrendorzhieva A. V. Lis M. G. Voronkov 《Russian Journal of General Chemistry》2011,81(12):2501-2505
N-Organylbis(trimethylsilyl)amines of the general formula RN(SiMe3)2 (R = Me3Si, Et3Ge) were synthesized by reaction of sodium bis(trimethylsilyl)amide with the corresponding trialkylsilyl(germyl) halide. Their
IR, UV, and 1H, 13C, and 29Si NMR spectra were studied, and saturated vapor pressures and thermal stabilities were determined. The possibility of using
the RN(SiMe3)2 compounds as precursors in chemical vapor deposition of films with specified composition was estimated by thermodynamic modeling. 相似文献
19.
Lidiya I. Kursheva Olga N. Kataeva Dmitry B. Krivolapov Aidar T. Gubaidullin Elvira S. Batyeva Oleg G. Sinyashin 《Heteroatom Chemistry》2008,19(5):483-489
Some Cu(I) halides complexes based on P(III) acid esters,{[(RE)3PCuBr] (where E = O, N, S); R = n‐Pr, i‐Pr, Et2N} were obtained and characterized using IR, 31P NMR spectroscopy, and single crystal X‐ray diffraction. The comparative structural characteristics of complexes with various donor atoms (E = O, N, S) are analyzed. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:483–489, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20459 相似文献
20.
Igor V. Ukrainets Svitlana V. Shishkina Vyacheslav N. Baumer Olga V. Gorokhova Lidiya A. Petrushova Galina Sim 《Acta Crystallographica. Section C, Structural Chemistry》2016,72(5):411-415
The fact that molecular crystals exist as different polymorphic modifications and the identification of as many polymorphs as possible are important considerations for the pharmaceutic industry. The molecule of N‐benzyl‐4‐hydroxy‐1‐methyl‐2,2‐dioxo‐1H‐2λ6,1‐benzothiazine‐3‐carboxamide, C17H16N2O4S, does not contain a stereogenic atom, but intramolecular hydrogen‐bonding interactions engender enantiomeric chiral conformations as a labile racemic mixture. The title compound crystallized in a solvent‐dependent single chiral conformation within one of two conformationally polymorphic P212121 orthorhombic chiral crystals (denoted forms A and B). Each of these pseudo‐enantiomorphic crystals contains one of two pseudo‐enantiomeric diastereomers. Form A was obtained from methylene chloride and form B can be crystallized from N,N‐dimethylformamide, ethanol, ethyl acetate or xylene. Pharmacological studies with solid–particulate suspensions have shown that crystalline form A exhibits an almost fourfold higher antinociceptive activity compared to form B. 相似文献