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101.
To prepare structure-ordered GaAs(001) surfaces at low temperatures, GaAs(001) surfaces coated with native oxides were exposed in an atomic hydrogen flow in the temperature range 280–450 °C. The new Ga-enriched GaAs(001) surfaces with the (4 × 4) and (2 × 4)/c(2 × 8) reconstructions were prepared and studied by the methods of X-ray photoelectron spectroscopy, low-energy electron diffraction, and high-resolution characteristic electron energy loss spectroscopy. For the GaAs(001)-(2 × 4) surface, the structure of the Ga-stabilized surface has been proposed and ab initio computed within the (2 × 4) Ga-trimer unit cell model. 相似文献
102.
The selective interaction of the iodine and cesium atoms with the GaAs(001) surface, which leads to a decrease in the bond energy of the Ga and As surface atoms, respectively, owing to the redistribution of the electron density in the near-surface region under the effect of electronegative and electropositive adsorbates, has been experimentally investigated. This selective interaction makes it possible to remove alternately the Ga and As monolayers in the iodine and cesium adsorption followed by heating at T ≤ 450°C and, thus, to implement reversible low-temperature transitions between the Ga-and As-stabilized superstructures, as well as the atomic layer etching of the semiconductor with the physically ultimate monolayer accuracy. 相似文献
103.
Getmanova E. V. Tereshchenko A. S. Ignat"eva G. M. Tatarinova E. A. Myakushev V. D. Muzafarov A. M. 《Russian Chemical Bulletin》2004,53(1):137-143
A universal method for the synthesis of hydrophilic dendrimers was considered. The method is based on a combination of carbosilane dendrimers with different molecular organizations and hydrophilizing agents, viz., substituted hydride silanes containing one and three protected hydroxyl groups. The combination of a limited set of the mentioned reagents makes it possible to control the ratio of hydrophilic and hydrophobic moieties of the molecular structure in wide limits. A simple and convenient method for the removal of trimethylsilyl protection of hydroxyl groups in the surface layer of dendrimers was developed. 相似文献
104.
A. A. Pakhnevich V. V. Bakin A. V. Yaz’kov G. É. Shaibler S. V. Shevelev O. E. Tereshchenko A. S. Yaroshevich A. S. Terekhov 《JETP Letters》2004,79(10):479-483
Energy distributions of photoelectrons emitted into vacuum from the valence band and the localized states in the energy gap of p-GaN(Cs, O) with effective negative electron affinity were studied. It is shown that the photothermal electron excitation from the localized states lying below the Fermi level in the energy gap of p-GaN(Cs, O) is the dominant photoemission mechanism at the low-energy photoemission threshold. 相似文献
105.
I. M. Tkachenko A. I. Kovalchuk Ya. L. Kobzar O. V. Shekera O. G. Tereshchenko 《Molecular Crystals and Liquid Crystals》2020,697(1):85-96
AbstractThe aim of this work is to study the optical properties of the core-fluorinated azo-containing polyazomethines with 1,4-tetrafluorobenzene or 4,4′-octafluorobiphenylene dioxyphenylene units and aliphatic fragments in the chain. Due to the reorganization process at the nanometer-scale under UV/Vis irradiation, azo-containing polymers (APs) have attracted much attention as materials for biology, optoelectronics, nano-manipulation field, etc. Moreover, the introduction of azomethine group into these polymers enhances not only their optical properties but also expands their practical application. APs polymers have the useful combination of chemical and physical properties such as liquid crystalline states, high nonlinearity and an ability to form metal complexes. It was shown that the optical properties of such polymers could be improved by the inclusion of fluorine. Fluorinated polymers demonstrate high thermal stability and have low dielectric constant and dielectric losses. It should be noted that the presence of flexible moieties in a polymer backbone allows regulating the different properties (solubility, thermostability, optical and liquid crystalline properties) of the final materials. 相似文献
106.
D.?A.?MirzayevEmail author I.?L.?Yakovleva N.?A.?Tereshchenko V.?N.?Urtsev 《Bulletin of the Russian Academy of Sciences: Physics》2012,76(1):23-26
The structure of Fe-5.5% Cu alloy is studied after eutectoid reaction and aging of the martensite. The thermodynamic analysis
of decomposition of the supersaturated solid solution with copper release is peformed for different types of crystal lattice.
The free energy of solid solutions and phase separation diagrams of the BCC and FCC phases of copper is calculated. Barriers
for the nucleation of copper particles with BCC and FCC lattices are evaluated. The factors that favor the appearance of intermediate
structural forms of copper preceding the formation of stable FCC phase are discussed. 相似文献
107.
D. S. Tereshchenko I. V. Morozov A. I. Boltalin E. V. Karpova T. Yu. Glazunova S. I. Troyanov 《Crystallography Reports》2013,58(1):68-77
A series of fluoro(trifluoroacetato)metallates were synthesized by crystallization from solutions in trifluoroacetic acid containing nickel(II) or cobalt(II) nitrate hydrates and alkali metal or ammonium fluorides: Li[Ni3(μ3-F)(CF3COO)6(CF3COOH)3](CF3COOH)3 (I), M′[Ni3(μ3-F)(CF3COO)6(CF3COOH)3] (M′ = Na (II), NH4 (IV), Rb (V), and Cs (VI)), NH4[Co3(μ3-F) (CF3COO)6(CF3COOH)3] (III), and Cs[Ni3(μ3-F)(CF3COO)6(CF3COOH)3](CF3COOH)0.5 (VII). The crystal structures of these compounds were determined by single-crystal X-ray diffraction. All structures contain triangular trinuclear complex anions [M 3″(μ3-F)(CF3COO)6(CF3COOH)3]? (M″ = Ni, Co) structurally similar to trinuclear 3d metal oxo carboxylate complexes. The three-coordinated F atom is located at the center of the triangle formed by Ni(II) or Co(II) atoms. The metal atoms are linked in pairs by six bridging trifluoroacetate groups located above and below the plane of the [M″3 F] triangle. The oxygen atoms of the axial CF3COOH molecules complete the coordination environment of M″ atoms to an octahedron. 相似文献
108.
Yu. A. D’yakova E. I. Suvorova A. S. Orekhov A. S. Alekseev V. V. Klechkovskaya E. Yu. Tereshchenko N. V. Tkachenko H. Lemmetyinen L. A. Feigin M. V. Kovalchuk 《Crystallography Reports》2011,56(1):157-163
Monolayers of porphyrin-fullerene dyad TBD6a were formed on the surface of a water subphase and then transported on a solid
substrate by the Langmuir-Schaefer method. A simulation was performed for the structure of a single molecule and for a molecular
monolayer, according to the area per molecule in the monolayer formed, which was calculated based on an analysis of the π-A
isotherm. A unit cell was chosen for the proposed molecular packing (a = 1.54 nm, b = 1.50 nm, c = 1.75 nm, α = 80.0°, β = 90.0°, and γ = 90.0°), and the atomic coordinates were calculated. A comparison of the interplanar
spacings and diffraction peak intensities in the experimental and calculated (for the unit cell proposed) diffraction patterns
indicates that a platelike texture is formed in the monolayer and that the crystal structure of the domains corresponds to
the model chosen. 相似文献
109.
T. T. Todosiichuk L. N. Yashchenko V. N. Tereshchenko A. N. Gorbatenko 《Polymer Science Series D》2011,4(3):172-176
The results of investigating the effects of various fire retardants on the fire-resistance of epoxy urethane compositions
are presented. It is shown that the simultaneous presence of phosphorus and bromine, as well as oxides and hydroxides, favors
efficient coke formation and a reduction in combustibility while retaining the physicomechanical characteristics of an epoxy
urethane adhesive. 相似文献
110.
Yu. P. Porshnev E. M. Tereshchenko V. B. Mochalin 《Chemistry of Heterocyclic Compounds》1974,10(10):1156-1158
2,5-Dibutoxy-4-(α-thienyl)-Δ3-dihydropyran was obtained by bromoalkoxylation at the double bond and dehydrobromination of 2-butoxy-4-(α-thienyl)-Δ5-dihydropyran. Acid hydrolysis of the product in the presence of N-methylaniline hydrochloride gave a salt of 3-(α-thienyl)glutaconic dialdehyde dianil, treatment of which with cyclopentadienylsodium in alcohol gives the corresponding fulvene, which is thermally cleaved to N-methylaniline and 6-(α-thienyl)azulene. 相似文献