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11.
Myshkina O. A. Balandina S. Yu. Makhmudov R. R. Dmitriev M. V. Lisovenko N. Yu. 《Russian Chemical Bulletin》2021,70(7):1408-1414
Russian Chemical Bulletin - The reaction of 1-substituted 4,4,4-trichloromethylbutane-1,3-diones with o-phenylenediamine afforded 4-substituted 2-trichloromethyl-3H-1,5-benzodiazepines with... 相似文献
12.
V. N. Nesterov S. S. Nagapetyan V. E. Shklover Yu. T. Struchkov S. V. Amosova A. N. Nikol'skaya N. V. Myshkina M. G. Voronkov 《Russian Chemical Bulletin》1995,44(9):1711-1714
The structure of bis(2-sodiumsulfonylethyl) sulfoxide hexahydrate (1), which was synthesized by the reaction of divinyl sulfoxide with sodium metabisulfite in an aqueous ethanol medium, has been determined by X-ray structural analysis. Both Na+ cations are coordinated by six O atoms of crystallization water molecules and SO3 groups; the coordination sphere is a distorted octahedron. The crystals are stabilized by an extensive network of hydrogen bonds through the water molecules of crystallization. 相似文献
13.
V. A. Livshits A. P. Bonartsev A. L. Iordanskii E. A. Ivanov T. A. Makhina V. L. Myshkina G. A. Bonartseva 《Polymer Science Series B》2009,51(7-8):256-263
The kinetics of the controlled release of the antiproliferative drug dipyridamole from microspheres based on the biocompatible and biodegradable polymer poly(3-hydroxy)butyrate is studied. As carriers for dipyridamole, microspheres prepared from a solution of poly(3-hydroxy)butyrate by single emulsion method are used. Under in vitro conditions, the kinetic curves describing the release of dipyridamole from microspheres with diameters of 19, 63, and 92 μm show two characteristic regions: the region of fast drug release within a short time period and a well-pronounced continuous linear region. For microspheres with a diameter of 4 μm, the linear region is missing. Analysis of the kinetic curves illustrating controlled drug release together with the measurements on polymer degradation shows that their kinetic profiles depend on the diffusion-controlled process and hydrolytic degradation of poly(3-hydroxy)butyrate. The diffusion kinetic equation describing both linear and nonlinear regions of dipyridamole released from the microspheres involves the sum of two terms: desorption from the sphere via the diffusion-controlled mechanism and drug release via the zero-order reaction. The linear region of the drug release curve is explained by the zero-order hydrolysis of poly(3-hydroxy)butyrate. The diffusion coefficients and kinetic constants are calculated. For bigger microspheres, the existence of the continuous linear region in the corresponding kinetic curves makes it possible to use microsystems based on poly(3-hydroxy)butyrate and dipyridamole as novel systems for local prolonged drug delivery. 相似文献
14.
15.
Reaction of 2-mercapto-3-amino-5,6-dimethyl- and 2-mercapto-3-amino-5,6-diphenylpyrazines withα-halo acid esters gave 2-carbethoxy-3-aminopyrazines, which are converted by the action of sodium ethoxide to 5,6-dimethyl- and 5,6-diphenylpyrazino[2,3-b]-[1,4]thiazin-6-ones. The latter are more conveniently obtained from 2-chloro-3-amino-5,6-dimethyl- and 2-chloro-3-amino-5,6-diphenylpyrazines and thioglycolic acid. 5,6-Dihydropyrazinothiazine is formed by reduction of 5,6-dimethyl pyrazino[2,3-b][1,4]thiazin-6-one, whereas the 2,3-dimethyl-5-amino-6-sulfonic acid and its N-oxide are formed by oxidation. 相似文献
16.
17.
T. S. Safonova L. A. Myshkina V. A. Chernov A. I. Kravchenko 《Chemistry of Heterocyclic Compounds》1967,3(4):287-290
Esters of orotylamino acid are synthesized by reacting orotyl chloride with glycine andα- andβ-alanine esters. Orotylamino acids are prepared by reducing the benzyl ester of orotylglycine, or by reacting orotyl chloride with sodium salts of amino acids. A series of salts of orotic acid are prepared by reacting orotic acid with amines. 相似文献
18.
S.N. Mikhailenko VL.G. TyuterevV.I. Starikov K.K. AlbertB.P. Winnewisser M. Winnewisser G. MellauC. Camy-Peyret R. LanquetinJ.-M. Flaud J.W. Brault 《Journal of Molecular Spectroscopy》2002,213(2):91-121
Water vapor infrared spectra have been recorded at room temperature in the range 4200-6250 cm−1 at resolutions (FWHM) between 0.0053 and 0.0080 cm−1. The use of a White-type multireflection cell made large pressure × pathlength products possible up to 31.27 mbar×288.5 m. The high signal-to-noise ratio allowed us to observe lines with intensities as small as 10−26 cm−1/molecule cm−2 at T=296 K. Among about 5100 recorded water lines, about half of which are reported for the first time, 2351 lines have been assigned to the second triad of H216O (bands ν1+ν2, ν2+ν3, and 3ν2). This has allowed the determination of line positions and corresponding upper rovibrational states with considerably improved accuracy. The assignments of certain highly excited states have been confirmed by the analysis of flame spectra and hot emission spectra. New values of effective Hamiltonian parameters for the upper states {(110), (030), (011)} have been determined. The generating function model was used in the data reduction to account for the anomalously strong centrifugal distortion of the rovibrational levels and resonance interactions. The RMS standard deviation of the least-squares fit of the assigned H2O data was 5×10−3 cm−1 for line positions and 7×10−3 cm−1 for energy levels up to Jmax=20 and Ka(max)=13. Particular attention was paid to water lines in the transparency window 4200-5000 cm−1, in which existing databases are not sufficient. In this region, 1395 lines of four isotopic species of water have been recorded and over 900 accurate line positions of nine bands of H216O (ν1, ν3, 2ν2, ν1+ν2, ν2+ν3, 3ν2, 4ν2−ν2, 2ν2+ν3−ν2, ν1+2ν2−ν2) are reported in this range. A comparison of laboratory spectra with long path atmospheric spectra (20 km slant path in the mountains) in this region shows that many lines missing from available spectroscopic compilations (or considerably shifted compared to observations) are important for a proper interpretation of atmospheric observations. A comparison of the observed data with the best available predictions from the molecular electronic potential energy surface is discussed. 相似文献
19.
Stability radii for some propagation models 总被引:2,自引:0,他引:2
The simple idea of Hinrichsen & Pritchard who defined thestructured stability radius has proved to be unexpectedly fruitful,generating a large amount of work and making interesting connections.The aim of this paper is twofold: to study stability radii forsome specific propagation models and to make connections withresults on Popov-type frequency-domain stability inequalities. 相似文献
20.
Rare earth element substituted bismuth ferrites (BiFeO3) are of enormous importance as magnetoelectric materials. The polycrystalline samples of Bi
x
La1−x
FeO3 (x=0, 0.2, 0.4, 0.6, 0.8) were prepared by solid-state reaction using standard ceramic method. The single-phase formation of
these compounds was confirmed by X-ray diffraction (XRD) studies. The samples with x=0, 0.2, 0.4, 0.6 are found to be orthorhombic while the sample with x=0.8 is triclinic. The dielectric constant (ε′) and dissipation factor (tan δ) were measured in the frequency range 100 Hz
to 1 MHz at room temperature and as a function of temperature at certain fixed frequencies (1 kHz, 10 kHz, 100 kHz, 1 MHz).
All the samples showed dielectric dispersion. The dielectric constant with temperature shows a broad peak; the peak temperature
shifts with frequency which reflects the relaxor-type behavior. The peak above 600 K in the measured temperature range corresponds
to antiferromagnetic ordering temperature (Néel temperature). The broadness of the peak changes with composition. The ac conductivity
as well as ε′ are found to be maximum for the sample x=0.2 at room temperature. 相似文献