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921.
A. V. Turik A. I. Chernobabov G. S. Radchenko S. A. Turik 《Physics of the Solid State》2004,46(12):2213-2216
Effective complex piezoelectric and dielectric constants of disordered heterogeneous systems, such as statistical mixtures consisting of spheroidal particles of the same orientation but with random distribution in space, are studied. It is found for the first time that, in such systems, there exists giant piezoelectric enhancement accompanied by giant relaxation of piezoelectric coefficients and permittivity. The piezoelectric and dielectric spectra differ considerably from the Debye spectra and have a Cole-Cole character. The dependence of the effects considered on the aspect ratios of the spheroids is investigated. The physical mechanisms responsible for the anomalous behavior of the piezoelectric coefficients and permittivity are considered. 相似文献
922.
O. P. Bobrov S. N. Laptev H. Neuhäuser V. A. Khonik K. Csach 《Physics of the Solid State》2004,46(10):1863-1867
Isochronous relaxation of tensile stresses is measured in a bulk Pd40Cu30Ni10P20 metallic glass in the initial state and after certain thermal treatments. The results of measurements are used to find the energy spectrum of irreversible structural relaxation, from which the temperature dependence of shear viscosity is then calculated. This dependence is also found independently from measurements of creep in the same glass. The calculated viscosity is shown to agree well with the experimental data. 相似文献
923.
V. V. Dvorkin N. N. Dzbanovskii A. F. Pal’ N. V. Suetin A. Yu. Yur’ev P. Ya. Detkov 《Physics of the Solid State》2004,46(4):729-732
A suspension of ultrafine-dispersed nanodiamond was used for introducing (in particular, selectively) high-density centers of diamond nucleation on various substrates. High-quality doped diamond films to be used as electrochemistry electrodes were deposited from the gas phase in a microwave discharge on certain substrates treated using ultrafine-dispersed nanodiamond. A uniform distribution of nucleation centers with concentrations greater than 1010 cm-2 on silicon substrates was obtained. Electrochemical current-potential curves were measured for continuous films. Diamond meshes of different transparency were grown using selective nucleation. Successful production of high-quality doped diamond meshes gives grounds to consider them the most promising electrodes for use in electrochemistry. 相似文献
924.
It is found that, when a bismuth crystal is subjected simultaneously to concentrated loading and a dc magnetic field, the magnetoplastic effect manifests itself as an abrupt decrease in the average length of wedge twins on the (111) cleavage plane (and, hence, as a decrease in the total twinned volume of the crystal) as a threshold value of the magnetic field is reached. However, the magnetic field stimulates glide deformation, which is indicated by an increase in the size of dislocation rosettes. The microhardness of a crystal varies smoothly and tends to increase with increasing magnetic field. The last phenomenon is accounted for by hardening of the crystal under the indenter in the presence of a magnetic field, because several slip systems become operative. 相似文献
925.
In terms of two-dimensional dislocation-disclination dynamics, a theoretical model is developed to describe the decay of a low-angle tilt boundary in a deformed nanocrystalline material under the action of an externally applied elastic stress and of the elastic field of a neighboring decayed boundary. The critical external stresses are calculated at which the boundary decays and the dislocations making up this boundary either are trapped by the boundary that decayed earlier or break away from both boundaries. The decay of a low-angle tilt boundary is shown to result in a substantial decrease in the critical decay stresses for the neighboring boundaries, which can cause an avalanche-like chain decay of low-angle boundaries yielding high-density ensembles of mobile dislocations capable of carrying substantial plastic deformations and of forming shear bands in deformed nanocrystalline materials. 相似文献
926.
The translational nonequilibrium zone in a shock wave is considered for a gas consisting of light particles and a small addition
of heavy particles. The gas is taken to be two-dimensional, and long-range forces are assumed to be absent. In the framework
of this approximation, a program for molecular dynamics simulation of the gas is developed. It is applied to calculate a particle
distribution function in the shock wave, to analyze the time evolution of the distribution function, and to study its dependence
on the gas composition. 相似文献
927.
O. Yu. Borkovskaya N. L. Dmitruk I. B. Ermolovich R. V. Konakova V. V. Milenin 《Technical Physics》2004,49(3):325-329
The properties of nonrectifying AuGe/GaAs (Al0.4Ga0.6As) contacts exposed to heat treatment, 60Co γ radiation, and γ radiation combined with the application of an electrical bias are studied. A correlation between the
type of interfacial interaction in the contacts and their resistance is found. Results obtained are explained in terms of
a diffusion model with a movable boundary of the metal layer. 相似文献
928.
The structure, composition, and mechanical properties of iron-alloyed TiC-TiNi composite materials are studied. When the titanium
carbide framework is sintered with iron and then impregnated with titanium nickelide, iron atoms are found to diffuse into
the matrix and form the B2 structure that is inhomogeneous (gradient) in chemical composition and properties and exhibits various temperatures of martensitic
transformation. The latter fact shows up in the broadening of the martensitic transformation hysteresis and its shift toward
low temperatures with increasing iron content. At room temperature, the strength properties of gradient-matrix TiC-TiNi composites
are shown to increase with iron concentration. 相似文献
929.
Russian Physics Journal - 相似文献
930.
Russian Physics Journal - 相似文献