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121.
122.
B. A. Polezhaev T. A. Prokof’ev A. V. Kovalenko M. F. Bulanyi 《Journal of Applied Spectroscopy》2006,73(5):707-713
By means of comprehensive analysis of the temperature dependences of the photoluminescence for ZnS:Mn crystals, we have observed
persistent changes in the intensity, shape, and position of the maximum in the emission spectrum associated with changes in
the immediate environment of the manganese luminescence centers. We have also observed inflection points on the voltage vs.
brightness characteristics of the samples, the position of which depends on the frequency of the exciting voltage and the
temperature. The observed dependences are explained using concepts describing the mechanisms of pre-breakdown luminescence.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 5, pp. 631–636, September–October, 2006. 相似文献
123.
V.L. Kovalenko V.A. Kotok A.A. Sykchin I.A. Mudryi B.A. Ananchenko A.A. Burkov V.A. Sololvov S. Deabate A. Mehdi J.-L. Bantignies F. Henn 《Journal of Solid State Electrochemistry》2017,21(3):683-691
Hybrid supercapacitors with nickel hydroxide electrode are widely used as modern power sources for electrovehicles, ignition of different electric engines, etc. Nickel hydroxide for supercapacitor use must satisfy special features which are quite different from those requested for battery application. The aim of this work is to improve the promising two-stage high-temperature method by altering hydrolysis condition (hot and cold) in order to obtain Ni(OH)2 with improved electrochemical activity. Ni(OH)2 samples have been investigated by PXRD, TG, DSC, SEM, TEM, cyclic voltammogramm, and galvanostatic charge-discharge cycling. It has been established from PXRD, TG, and DSC analyses that material obtained by hydrolysis at high temperature is a highly crystalline β-Ni(OH)2 characterized by high thermal stability. Materials prepared by cold hydrolysis are a highly defective βbc-Ni(OH)2, with 6.3 % water content and a lower thermal stability. It has been shown that samples prepared by hot hydrolysis have a high redox reversibility and electrochemical cycling stability, but a lower electrochemical capacity. This suggests that the electrochemical processes are localized in the thin layer at the particle surface. Cyclic voltammograms of samples prepared by cold hydrolysis exhibit gradual activation of the active material, anyhow resulting in higher capacity. By means of the galvanostatic charge-discharge curves at different current densities, the specific capacities of the samples have been calculated. The sample prepared by cold hydrolysis has higher specific capacities than the sample prepared by hot hydrolysis. 相似文献
124.
A. A. Kovalenko 《Fluid Dynamics》1995,30(4):555-562
A method of solving the boundary layer equations is developed taking into account the strong interaction between the boundary layer and the outer hypersonic inviscid flow. The method is aimed at solving problems whose salient feature is the possible upstream propagation of disturbances over distances comparable with the body length. The procedure for fitting a self-consistent contour of the effective body using an artificially formulated boundary value problem for an ordinary second-order differential equation, which lies at the basis of the method, is considered in detail. The method is applied to the problem of flow around a flat plate with roughness in the form of an embankment or a trench; the calculated results are presented.Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 4, pp. 81–89, July–August, 1995. 相似文献
125.
O. I. V’yunov O. N. Gavrilenko L. L. Kovalenko S. A. Chernukhin L. O. Vasilechko S. D. Kobilyanskaya A. G. Belous 《Russian Journal of Inorganic Chemistry》2011,56(1):93-98
The structural features and electrophysical properties of lithium-conducting compounds having defect perovskite structure
based on Li0.5La0.5Nb2O6 and Li0.5La0.5TiO3 were studied using X-ray diffraction and synchrotron analyses, potentiometry, and complex impedance spectroscopy. Intercalated
lithium was found to differently influence ion conductance in titanium- and niobium-containing materials. This difference
was found to arise from the structural features of the materials. The systems studied have high chemical diffusion coefficients
of lithium (D
Li+ = 1 × 10−6 cm2/s for Li0.5La0.5Nb2O6 and D
Li+ = 3.3 × 10−7 cm2/s for Li0.5La0.5TiO3). 相似文献
126.
M. Yu. Koroleva D. A. Kovalenko V. M. Shkinev O. N. Katasonova B. Ya. Spivakov E. V. Yurtov 《Russian Journal of Inorganic Chemistry》2011,56(1):6-10
We studied the influence of synthesis parameters and the composition of the reaction mixture on the size and morphology of
copper nanoparticles (NPs). Use of a surfactant (polyoxyethylenesorbitan monooleate) is promising for confining NP growth
and stabilizing NPs. Concentration ranges of existence were determined for copper NP dispersions stable to aggregation and
sedimentation. Scanning electron microscopy and dynamic light scattering were used to show that: the NP size varied from 10
to 65 nm, the average diameter was 25–35 nm, and the shape was spherical. The sizes of copper NP aggregates were determined. 相似文献
127.
Nag A Kovalenko MV Lee JS Liu W Spokoyny B Talapin DV 《Journal of the American Chemical Society》2011,133(27):10612-10620
All-inorganic colloidal nanocrystals were synthesized by replacing organic capping ligands on chemically synthesized nanocrystals with metal-free inorganic ions such as S(2-), HS(-), Se(2-), HSe(-), Te(2-), HTe(-), TeS(3)(2-), OH(-) and NH(2)(-). These simple ligands adhered to the NC surface and provided colloidal stability in polar solvents. The versatility of such ligand exchange has been demonstrated for various semiconductor and metal nanocrystals of different size and shape. We showed that the key aspects of Pearson's hard and soft acids and bases (HSAB) principle, originally developed for metal coordination compounds, can be applied to the bonding of molecular species to the nanocrystal surface. The use of small inorganic ligands instead of traditional ligands with long hydrocarbon tails facilitated the charge transport between individual nanocrystals and opened up interesting opportunities for device integration of colloidal nanostructures. 相似文献
128.
M. B. Gazizov V. V. Zverev R. A. Khairullin R. R. Shagidullin A. I. Alekhina L. V. Avvakumova V. I. Kovalenko O. G. Sinyashin 《Russian Journal of General Chemistry》2011,81(4):647-657
O,O-Dialkyl [1-hydroxy-3-(dialkylamino)-2,2-dimethylpropyl]phosphonates were prepared for the first time. By means of NMR 1H, IR spectroscopy and quantum-chemical calculations the presence in them of various H-bonds was established. In the crystalline
state P=O…HO intermolecular hydrogen bonds favor the formation of cyclic dimer associates D
P=O. In the liquid state and concentrated solutions P=O…HO and N…HO intermolecular hydrogen bonds cause the formation of cyclic
dimer associates D
P=O and DN, and intramolecular hydrogen bonds provide the existence of different conformations of the monomer form MN, the most stable
among them with the non-strained six-membered …NCCCOH… ring. 相似文献
129.
All nine isolated-pentagon-rule isomers of fullerene C(82) were investigated by the DFT method with the B3LYP functional at the 6-31G, 6-31G*, and 6-31+G* levels. The distribution of single, double, and delocalized π-bonds in the molecules of these isomers is shown for the first time. The obtained results are fully supported by DFT quantum-chemical calculations of electronic and geometrical structures of these isomers. The molecules of isomers 7 (C(3v)), 8 (C(3v)), and 9 (C(2v)) contain some radical substructures (such as the phenalenyl-radical substructure), which indicates that they are unstable and cannot be obtained as empty molecules. Thus, there is a possibility of obtaining them only as endohedral metallofullerenes or exohedral derivatives. Isomers 1 (C(2)), 2 (C(s)), 4 (C(s)), 5 (C(2)), and 6 (C(s)) with closed electronic shell are supposed to be stable, resembling isomer 3 (C(2)), which has just been extracted experimentally as an empty fullerene. We assume they can be produced as empty molecules. 相似文献
130.
Kovalenko OO Brusylovets OA Kinzhybalo V Lis T Brusilovets AI 《Dalton transactions (Cambridge, England : 2003)》2011,40(18):4814-4817
The low-coordinate phosphorus compounds (Me(3)Si)(2)N-P=NSiMe(3), (Me(3)Si)(2)N-P(=S)=N(t)Bu and (Me(3)Si)(2)N-P(=NSiMe(3))(2) react with ((i)PrO)(3)M≡M(O(i)Pr)(3) (M = Mo, W) to form four- and five-membered metallacycles with intact endocyclic or exocyclic M≡M triple bonds. The first four-membered planar metallacycles, containing an M≡M triple bond were obtained in reaction with (Me(3)Si)(2)N-P=NSiMe(3). 相似文献