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131.
The mechanism of silicon epitaxy on porous Si(111) layers is investigated by the Monte Carlo method. The Gilmer model of adatom
diffusion extended to the case of arbitrary surface morphology is used. Vacancies and pendants of atoms are allowed in the
generalized model, the activation energy of a diffusion hop depends on the state of the neighboring positions in the first
and second coordination spheres, and neighbors located outside the growing elementary layer are also taken into account. It
is shown that in this model epitaxy occurs by the formation of metastable nucleation centers at the edges of pores, followed
by growth of the nucleation centers along the perimeter and the formation of a thin, continuous pendant layer. Three-dimensional
images of surface layers at different stages of epitaxy were obtained. The dependence of the kinetics of the epitaxy process
on the amount of deposited silicon is determined for different substrate porosities.
Pis’ma Zh. éksp. Teor. Fiz. 67, No. 7, 512–517 (10 April 1998) 相似文献
132.
Yu. G. Abov D. S. Denisov N. O. Elyutin S. K. Matveev Yu. I. Smirnov A. O. Éidlin F. S. Dzheparov D. V. L’vov 《Journal of Experimental and Theoretical Physics》1998,87(6):1195-1200
The asymptotic behavior of the spectra for large values of the scattering vector for the case of elastic multiple small-angle
neutron scattering (SANS) is investigated theoretically and experimentally. An expansion of the spectrum in terms of the reciprocal
of the magnitude of the momentum transfer is obtained taking account of the influence of the instrumental line. It is shown
that, to within some factor, the leading term of the expansion is identical to the differential single-scattering cross section
averaged over a statistical ensemble of particles; several subsequent terms in the expansion are calculated and the range
of applicability of the resulting expressions is determined. The asymptotic behavior of the multiple SANS spectrum is measured,
using a two-crystal neutron spectrometer, for samples of an HTSC ceramic, the alloy Fe-Ni, and Al powder. The agreement between
the experimental results and the theoretical predictions is analyzed.
Zh. éksp. Teor. Fiz. 114, 2194–2203 (December 1998) 相似文献
133.
I. M. Shmyt’ko A. N. Izotov N. S. Afonikova S. Vieira G. Rubio 《Physics of the Solid State》1998,40(4):687-690
The formation of polytypic modifications is observed in dislocation-free silicon single crystals under directional plastic
deformation. It is shown that the deformation-stimulated phase appears on the surface of the sample in the form of small grains
ranging from several hundred to several thousand angstroms in size. A twin structure in the individual grains is observed.
Fiz. Tverd. Tela (St. Petersburg) 40, 746–749 (April 1998) 相似文献
134.
The dynamics of defects with linear dimensions from ≈1 to ≈100 nm on a Au surface under load have been studied by means of
tunnelling microscopy. It is found that the origin, growth, and resorption of the defects is caused by displacements of bands
of material from 5 to 50 nm wide, parallel to the {111} slip planes. The defects can be separated into two groups: nonsteady-state
defects, whose lifetime does not exceed 15 min, while the depth is ⩽20 nm, and quasi-steady-state defects, with a lifetime
three orders of magnitude greater than the first. It is assumed that the nonsteady-state defects are formed when the ensemble
of dislocations is being reconstructed, while the quasi-steady-state defects are formed at the instant of formation of dislocation
substructures during the creep of the loaded metal.
Fiz. Tverd. Tela (St. Petersburg) 40, 2180–2183 (December 1998) 相似文献
135.
E. D. Éidel’man 《Technical Physics》1998,43(11):1275-1279
A theory is developed for a new type of transition — a change in the ratio of the longitudinal and transverse dimensions of
a convection cell as the thickness of a liquid layer is varied. A sudden change in the ratio of the cell dimensions takes
place because of a change in the predominant mechanism for excitation of convection. The governing influence of buoyancy forces
gives way to one of thermocapillary forces, and they in turn give way to the influence of thermoelectric forces for yet thinner
layers. As the layer thickness is reduced gradually at a fixed external heating, the ratio of the dimensions will take on
the values 0.7, 0.65, and 1, respectively.
Zh. Tekh. Fiz. 68, 7–11 (November 1998) 相似文献
136.
V. T. Astrelin A. V. Burdakov V. S. Koidan K. I. Mekler P. I. Mel’nikov V. V. Postupaev M. A. Shcheglov 《Journal of Experimental and Theoretical Physics》1998,86(3):489-500
This paper presents the results of experiments on two-stage heating of a dense plasma by a relativistic electron beam in the
GOL-3 facility. A dense plasma with a length of about a meter and a hydrogen density up to 1017 cm−3 was created in the main plasma, whose density was 1015 cm−3. In the process of interacting with the plasma, the electron beam (1 MeV, 40 kA, 4 μs) imparts its energy to the electrons of the main plasma through collective effects. The heated electrons, as they disperse
along the magnetic field lines, in turn reach the region of dense plasma and impart their energy to it by pairwise collisions.
Estimates based on experimental data are given for the parameters of the flux of hot plasma electrons, the energy released
in the dense plasma, and the energy balance of the beam-plasma system. The paper discusses the dynamics of the plasma, which
is inhomogeneous in density and temperature, including the appearance of pressure waves.
Zh. éksp. Teor. Fiz. 113, 897–917 (March 1998) 相似文献
137.
The optical absorption of GaAs crystals with thicknesses d=0.4−4.4 μm is measured in the exciton-polariton resonance region at a temperature of 1.7 K. As the thickness is reduced,
both a broadening of the exciton line and increased absorption with a negligible Stark shift are observed. The way the absorption
spectra vary with crystal thickness is examined in terms of a competition between two regions for light-exciton interactions
in the crystal: in the field of surface charges and electric-field free.
Fiz. Tverd. Tela (St. Petersburg) 40, 869–871 (May 1998) 相似文献
138.
S. O. Romanovskii A. V. Sel’kin I. G. Stamov N. A. Feoktistov 《Physics of the Solid State》1998,40(5):814-815
A study is made of the effect of electric fields on the exciton states of β-ZnP2 crystals (T=77 K) in structures with Schottky barriers formed by depositing semitransparent electrically-conducting InSnO2 films on the crystal surface. The observed changes in the exciton optical reflection spectra when an electrical potential
is applied to a barrier are explained by the shift and broadening of the exciton level caused by the Stark effect. The experimental
data are compared with calculations based on a theory of exciton optical reflection from planar spatially nonuniform structures.
Fiz. Tverd. Tela (St. Petersburg) 40, 884–886 (May 1998) 相似文献
139.
A near-field scanning optical microscope (NSOM), which we built, is used to investigate 1–5-μm wide stripes with a 10-nm thick
layer—a quantum well — on a GaAs surface. A map of the photoluminescence intensity is obtained synchronously with the topographic
profile of the structures. The measured spatial distribution of the photoluminescence intensity is described satisfactorily
in a model that takes into account carrier diffusion in the layer and the existence of a region with a short carrier lifetime
near the side boundaries of the layer.
Pis’ma Zh. éksp. Teor. Fiz. 63, No. 7, 523–527 (10 April 1996) 相似文献
140.