全文获取类型
收费全文 | 123篇 |
免费 | 0篇 |
专业分类
化学 | 82篇 |
力学 | 5篇 |
数学 | 17篇 |
物理学 | 19篇 |
出版年
2021年 | 3篇 |
2020年 | 4篇 |
2019年 | 5篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 7篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 3篇 |
2012年 | 4篇 |
2011年 | 4篇 |
2010年 | 4篇 |
2009年 | 3篇 |
2008年 | 4篇 |
2007年 | 3篇 |
2006年 | 3篇 |
2005年 | 3篇 |
2004年 | 1篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 3篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 3篇 |
1971年 | 2篇 |
1970年 | 4篇 |
1969年 | 4篇 |
1968年 | 2篇 |
1966年 | 2篇 |
1965年 | 1篇 |
1964年 | 2篇 |
1963年 | 2篇 |
排序方式: 共有123条查询结果,搜索用时 46 毫秒
11.
The v(OH) frequency shifts of phenol and the vR resonance components of these shifts in the IR spectra of phenol H-complexes with ethylene derivatives containing various substituents including organosilicon, organogermanium, and organotin groups have been studied. The relationship between v and vR and the values that characterize the influence of substituents on the effective charges of the double bonded carbon atoms was established; the latter values have been calculated previously usingab initio quantum chemical methods. The effective charges for the compounds with organoelemental substituents have been calculated. It has been elucidated that of the two types of possible interactions, charge controlled and orbital controlled, occurring in the formation of a complex of a hard acid, phenol, with the studied ethylene derivatives, the former is predominant.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1383–1387, August, 1993. 相似文献
12.
Natalya N. Smirnova Tatiana G. Kulagina Larisa A. Smirnova Alla E. Mochalova Lyudmila Ya. Tsvetkova Ya. S. Samosudova Maksim B. Kiseliov Evgeny V. Sevast’yanov 《Journal of Thermal Analysis and Calorimetry》2013,112(3):1447-1452
For the first time, the heat capacity $ C_{\text{p}}^{^\circ } $ of poly(2-ethylhexyl acrylate) has been studied in an adiabatic vacuum calorimeter between 7 and 350 K, the standard thermodynamic functions: heat capacity $ C_{\text{p}}^{^\circ } $ (T), enthalpy H°(T) ? H°(0), entropy S°(T) ? S°(0), Gibbs function G°(T) ? H°(0) have been calculated from T → 0 to 350 K. The energy of combustion Δc U of the compound under study has been measured in a calorimeter with a stationary bomb and an isothermal shell. The standard enthalpy of combustion Δc H° and thermodynamic parameters of formation—enthalpy Δf H°, entropy Δf S°, Gibbs function Δf G°—at T = 298.15 K have been calculated. The results have been used to calculate the thermodynamic characteristics of 2-ethylhexyl acrylate bulk polymerization into poly(2-ethylhexyl acrylate) over the range from T → 0 to 350 K. 相似文献
13.
14.
K. I. Mikhailopulo T. S. Serchenya E. P. Kiseleva Yu. G. Chernov T. M. Tsvetkova N. V. Kovganko O. V. Sviridov 《Journal of Applied Spectroscopy》2008,75(6):857-863
We have used fluorescence spectroscopy methods to show that imidacloprid and its structural analogs form complexes with human
serum albumin (HSA). The nature of the spectral changes in the ligand×protein systems and the calculated complexation parameters
suggest that these low molecular weight compounds mainly bind to a specific section of the protein molecule, near the tryptophan
residue in the 214 position of the polypeptide chain. We have found that the association constants are on the order of 104 M−1, and the affinity of the ligands for HSA varies in the series 6-chloronicotinic acid > 6-methoxynicotinic acid = imidacloprid
> the keto analog of imidacloprid. The major contribution to the complexation energy probably comes from hydrophobic interaction
forces with participation of the aromatic pyridine ring of the ligands, while additional enhancement of ligand-protein affinity
can be provided by the nitroimine group of imidacloprid.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 6, pp. 859–866, November–December, 2008. 相似文献
15.
L. V. Borisova V. A. Ryabukhin O. D. Bozhkov Kh. Ts. Tsvetkova 《Journal of Analytical Chemistry》2010,65(5):535-541
Methods for the field determination of rhenium in plants have been developed. The speciation of rhenium in solutions throughout
the process of sample preparation has been investigated. It has been shown that, in the initial ethanol and water-salt extracts,
rhenium occurs as perrhenate ions. Perrhenate ions have been established to be partially reduced in time to give Re(VI). Since
test methods have been developed for determining rhenium as perrhenate-ions, their partial reduction in the process of sample
preparation can lead to an low level of the results. The optimal conditions for preserving rhenium as perrhenate ions have
been determined. Two procedures (in four versions) providing the determination of as low as 5 ng of rhenium in a 1-g sample
with an error below 23% have been proposed. The developed procedures have been applied in the places of the collection of
plant materials for the regional investigation of the occurrence of rhenium in the territories of different ore contents. 相似文献
16.
17.
Reactions of 6,6-dimethylfulvene with methyl diazoacetate in the presence of Cu compounds is accompanied by methoxycarbonylmethylenation
of the endocyclic double bonds to give the corresponding mono- and diadducts in total yields of up to 85% with marked predominance
ofanti-isomers. The subsequent cyclopropanation of monoadducts with diazomethane in the presence of Pd compounds also involves the
endocyclic double bond and gives esters of tricyclo[4.1.0.0.2,4]heptanecarboxylic acid in high yields.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 528–531, March, 1997. 相似文献
18.
19.
20.
N. Boshkov N. Tsvetkova D. Koleva G. Avdeev G. Raichevsky 《Applied Surface Science》2008,254(17):5618-5625
The anodic behavior, corrosion resistance and protective ability of Zn and alloyed Zn-Co (∼3 wt.%) nanocomposite coatings were investigated in a model corrosion medium of 5% NaCl solution. The metallic matrix of the layers incorporates core-shell nano-sized stabilized polymeric micelles (SPMs) obtained from poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) block co-polymers. The protective properties of the composite coatings were evaluated using potentiodynamic polarization technique, polarization resistance measurements and powder X-ray diffraction. The sizes and distribution of the stabilized polymeric micelles in the starting electrolytes used as well as in the metal matrices of the layers were investigated using scanning and transmission electron microscopy. The results obtained are compared to those of electrodeposited Zn and Zn-Co (∼3 wt.%) alloy coatings at identical conditions and demonstrate the enhanced protective characteristics of the Zn nanocomposites during the investigating period. The influence of the SPMs on the corrosion resistance of the nanocomposite layers is commented and discussed. 相似文献