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31.
M. V. Ryzhkov V. A. Gubanov Yu. A. Teterin A. S. Baev 《Zeitschrift für Physik B Condensed Matter》1985,59(1):7-14
The electronic structure of the heavy RE sesquioxides from Sm2O3 to Lu2O3 has been studied by the cluster discrete variational X method and X-ray photoelectron spectroscopy. The interpretation of XPS spectra basing on the MO model is given. An analysis of the dependence of Ln 4f orbitals contribution to chemical bonding on the lanthanide atomic number and bond lengths is made. 相似文献
32.
Mickhail V. Ryzhkov Alexei Mirmelstein Sung‐Woo Yu Brandon W. Chung James G. Tobin 《International journal of quantum chemistry》2013,113(16):1957-1965
Calculations of the electronic structure of clusters of plutonium have been performed, within the framework of the relativistic discrete‐variational method. These theoretical results and those calculated earlier for related systems have been compared to spectroscopic data produced in the experimental investigations of bulk systems, including photoelectron spectroscopy. Observation of the changes in the Pu electronic structure as a function of size provides powerful insight for aspects of bulk Pu electronic structure. © 2013 Wiley Periodicals, Inc. 相似文献
33.
One-electron guanine oxidation in DNA has been investigated in anionic reverse micelles (RMs). A photochemical method for generating Ru3+ from the ruthenium polypyridyl complex tris(2-2'-bipyridine)ruthenium(II) chloride ([Ru(bpy)3]Cl2) is combined with high-resolution polyacrylamide gel electrophoresis (PAGE) to quantify piperidine-labile guanine oxidation products. As characterized by emission spectroscopy of Ru(bpy)3(2+), the addition of DNA to RMs containing Ru(bpy)3(2+) does not perturb the environment of Ru(bpy)3(2+). The steady-state quenching efficiency of Ru(bpy)3(2+) with K3[Fe(CN)6] in buffer solution is approximately 2-fold higher than that observed in RMs. Consistent with the difference in quenching efficiency in the two media, a 1.5-fold higher yield of piperidine-labile damage products as monitored by PAGE is observed for duplex oligonucleotide in buffer vs RMs. In contrast, a 13-fold difference in the yield of PAGE-detected G oxidation products is observed when single-stranded DNA is the substrate. Circular dichroism spectra showed that single-stranded DNA undergoes a structural change in anionic RMs. This structural change is potentially due to cation-mediated adsorption of the DNA phosphates on the anionic headgroups of the RMs, leading to protection of the guanine from oxidatively generated damage. 相似文献
34.
V. M. Markushev M. V. Ryzhkov Ch. M. Briskina A. A. Borodkin S. I. Rumyantsev W. Z. Shen D. H. Xu V. L. Lyaskovskii 《Journal of Russian Laser Research》2012,33(2):122-127
We show that the laser spectra of ZnO films composed of particles that look like microtowers represent two bands with practically constant spectral distances between their peaks. By numerical analysis, we show that these two bands are due to whispering gallery modes (WGM), and one of these bands corresponds to the quasi-whispering gallery mode. Thus, we obtain here the first clear demonstration of the existence of quasi-WGMs, and show, in addition, that the width of the bands is caused by random spread of sizes of the ZnO particles in the lasing part. 相似文献
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36.
A. M. Nazarov E. M. Chainikova S. L. Khursan A. N. Ryzhkov R. L. Safiullin V. D. Komissarov 《Russian Chemical Bulletin》1998,47(7):1292-1295
The kinetics of self-termination of benzophenone oxide (BPO) in the liquid phase was studied by flash photolysis. The extinction
coefficient of BPO (ε) was found to be virtually independent of the solvent nature, ε=(1.9±0.1)·103 L mol−1 cm−1. The rate constant of the BPO self-temination increases from 1.8·107 (MeCN) and 7.4·107 (C6H6) to 1.5·109 (n-decane) and 2.0·109 L mol−1 s−1 (n-pentane) at 293±2 K. Solvation of BPO promotes a polar state of the molecule in MeCN and C6H6. In nonpolar hydrocarbons, a great contribution is made by the biradical structure resulting in an increase in the rate constant
and a shift of the absorption maximum to the long-wave region (from 410 nm in MeCN to 425 nm inn-pentane). In solutions of benzene and acetonitrile, benzophenone oxide reacts with the parent diazo compound with a rate
constant of (2–4)·105 L mol−1 s−1 (293±2 K) along with the self-termination.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1329–1332, July, 1998. 相似文献
37.
M. R. Talipov A. B. Ryzhkov S. L. Hursan R. L. Safiullin 《Journal of Structural Chemistry》2006,47(6):1051-1058
Density functional theory methods correctly describe some properties of nitrosooxides. Electronic spectral data have been calculated for seven para-substituted aromatic nitrosooxides in different solvents using the UB3LYP/6-311+G(d,p) approximation. The calculated positions of maxima in UV spectra correlate with experimental data with high coefficient. Equations are suggested for predicting the positions of absorption maxima for the para-R-C6H4-NOO under study. 相似文献
38.
39.
Dana Ferraris Brandon Young Christopher Cox Travis Dudding William J Drury Lev Ryzhkov Andrew E Taggi Thomas Lectka 《Journal of the American Chemical Society》2002,124(1):67-77
Methodology for the practical synthesis of nonnatural amino acids has been developed through the catalytic, asymmetric alkylation of alpha-imino esters and N,O-acetals by enol silanes, ketene acetals, alkenes, and allylsilanes using chiral transition metal-phosphine complexes as catalysts (1-5 mol %). The alkylation products, which are prepared with high enantioselectivity (up to 99% ee) and diastereoselectivity (up to 25:1/anti:syn), are protected nonnatural amino acids that represent potential precursors to natural products and pharmaceuticals. A kinetic analysis of the catalyzed reaction of alkenes with alpha-imino esters is presented to shed light on the mechanism of this reaction. 相似文献
40.