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941.
A. V. Ivanov Yu. E. Kalinin V. N. Nechaev A. V. Sitnikov 《Physics of the Solid State》2009,51(12):2474-2479
The concentration dependences of the electrical resistivity and complex permeability of [“(Co45Fe45Zr10)
x
(Al2O3)100 − x
”/“α-Si: H”]
n
multilayer structures and (Co45Fe45Zr10)
x
(Al2O3)100 − x
composites have been studied. It has been established that introduction of a semiconductor interlayer into the (Co45Fe45Zr10)
x
(Al2O3)100 − x
composites substantially decreases the electrical resistivity of [“(Co45Fe45Zr10)
x
(Al2O3)100 − x
”/“α-Si: H”]
n
multilayer structures. The concentration dependences of the real and imaginary parts of the complex permeability of the [“(Co45Fe45Zr10)
x
(Al2O3)100 − x
”/“α-Si: H”]
n
nanomultilayer structures substantially differ from those of the (Co45Fe45Zr10)
x
(Al2O3)100 − x
composites. The real part of the complex permeability of the [“(Co45Fe45Zr10)
x
(Al2O3)100 − x
”/“α-Si: H”]
n
nanomultilayer structures follows the curve with a minimum near the percolation threshold of the composite, and the imaginary
part smoothly decreases as the ferromagnetic phase concentration increases. The results obtained are explained by the increase
in the bifurcation temperature due to the conduction electrons of the semiconductor interlayer, which favor magnetic ordering
of ferromagnetic grains. 相似文献
942.
G. E. Remnev Yu. F. Ivanov E. P. Naiden M. S. Saltymakov A. V. Stepanov V. F. Shtan’ko 《Technical Physics》2009,54(4):600-602
Synthesis of silicon carbide and diamond nanoparticles is studied during short-pulse implantation of carbon ions and protons
into a silicon target. The experiments are carried out using a TEMP source of pulsed powerful ion beams based on a magnetically
insulated diode with radial magnetic field B
r
. The beam parameters are as follows: the ion energy is 300 keV, the pulse duration is 80 ns, the beam consists of carbon
ions and protons, and the ion current density is 30 A/cm2. Single-crystal silicon wafers serve as a target. SiC nanoparticles and nanodiamonds form in the surface layer of silicon
subjected to more than 100 pulses. The average coherent domain sizes in the SiC particles and nanodiamonds are 12–16 and 8–9
nm, respectively. 相似文献
943.
I. A. Ivanova V. T. Astrelin A. V. Burdakov R. V. Voskoboynikov A. I. Gorbovskii A. A. Ivanov V. A. Kapitonov S. G. Konstantinov K. N. Kuklin S. V. Polosatkin M. A. Tiunov 《Bulletin of the Lebedev Physics Institute》2009,36(11):325-326
To provide basic operations of semiconductor and radiation materials technologies, a multipurpose implanter with intense ion beams was developed at the Institute of Nuclear Physics. The generated beamparameters are as follows: ions are H+, O+; C+; the ion energy is up to 200 keV; the beam current is up to 2 mA; and the implantation mode is continuous. The size of the target to be processed can reach 76 × 76 mm2. During the implanter operation, the target chamber vacuum reaches 10?4 Pa. The entire process of target irradiation is fully automated. 相似文献
944.
A. Sissakian O. Shevchenko A. Nagaytsev O. Ivanov 《The European Physical Journal C - Particles and Fields》2009,59(3):659-673
We estimate the single-spin asymmetries (SSA) which provide the access to transversity as well as to Boer–Mulders and Sivers
PDFs via investigation of the single-polarized Drell–Yan (DY) processes with pp, pD and DD collisions available to RHIC, NICA, COMPASS, and J-PARC. The feasibility of these SSA is studied with the new generator of
polarized DY events. The estimations performed demonstrate that there exist kinematical regions where SSA are presumably measurable.
Most useful for PDFs extraction are the limiting kinematical ranges, where one can neglect the sea PDFs contributions which
occur at large values of the Bjorken variable x. It is of interest that, contrary to the Sivers PDF, the transversity PDF is presumably accessible only in a particular kinematical
region. Contrary to the option with the symmetric collider mode (RHIC, NICA), this is of importance for the COMPASS experiment
and the future J-PARC facility, where the fixed-target mode is available. 相似文献
945.
T. P. Akishina O. Yu. Denisova V. V. Ivanov S. A. Lebedev 《Physics of Particles and Nuclei Letters》2009,6(2):151-160
The comparison of the distributions of the e/π energy losses in the TRD prototype and GEANT3 simulation of the n-layered TRD realized in frames of the CBM ROOT at p = 1.5 GeV/c has shown that the GEANT3 simulation reproduces real data quite well. However, contrary to the real measurements, this does
not permit one to obtain a comparable level of pion’s suppression for GEANT3 data using the most powerful method based on
a likelihood functions ratio test. It is shown that the procedure of preparation of data sets corresponding to the n-layered TRD based on prototype measurements is a reason of reaching an erroneous and highly overestimated level of pion’s
suppression. It is also demonstrated that the needed level of pion’s suppression could be achieved using a combined method,
which is more simple for practical application.
The article is published in the original. 相似文献
946.
V. E. Kunitsyn E. D. Tereshchenko E. S. Andreeva V. F. Grigor’ev N. Yu. Romanova M. O. Nazarenko Yu. M. Vapirov I. I. Ivanov 《Moscow University Physics Bulletin》2009,64(6):661-663
The results of studying the structure of the ionospheric plasma distribution from data obtained at the transcontinental Russian
radio tomographic chain, which is the world’s longest, are presented. The 4000 km long tomographic chain extends from the
Svalbard Archipelago to Sochi. The unique feature of this upgraded radio tomographic system is that for the first time observations
cover a wide sector of the ionosphere from high latitudes (polar cap and auroral region) to low latitudes. This allows us
to study the transfer of perturbations in the system auroral-subauroral-midlatitude-low latitude ionosphere, and to analyze
ionospheric electron density distributions in different latitudinal regions as a function of different external factors and
solar-geophysical conditions. The first recent results speak for a complex structure of the ionospheric plasma, even in quiet
geophysical conditions (K
p
< 2.) 相似文献
947.
The spectra of the absorption coefficients of external radiation by basic chromophores of human skin, such as melanin, basic tissue, and blood (including oxy- and deoxyhemoglobin), are studied in the wavelength range of 300–1000 nm. For estimates, analytical methods of the theory of light transfer are used, which take into account the multilayer structure of a biological tissue, multiple light scattering in a medium, and multiple rereflections of radiation between layers. The calculated spectra are compared with the wavelength dependences of the absorption indices of these components available from the literature. It is shown that the spectral behaviors of the coefficients and indices of absorption strongly differ, which is related to the selectivity of the optical properties of a biological tissue. The possibilities of predicting the absorption coefficients of the skin components from the absorption coefficient of the entire skin measured under conditions of variation of its biophysical parameters (the volume concentrations of melanin and blood vessels) over a wide range are evaluated. 相似文献
948.
The probabilities of multiphoton transitions between the valence and conduction bands at two-photon resonance on the adjacent transition between two conduction bands are calculated within the three-band model of a crystal. It is shown that, due to the effects of transformation of electronic band spectrum in the field of a strong light wave, the dependence of the multiphoton generation rate of electron-hole pairs on the light intensity j contains ranges where a small change in j leads to an increase in the generation rate of electron-hole pairs by several orders of magnitude, which may increase the number of nonequilibrium carriers to the level sufficient for initiating destruction of the material. 相似文献
949.
A new mechanism for generating nonequilibrium electron-hole pairs in transparent wide-gap crystals under high-power picosecond
light pulses of prebreakdown intensity is considered. The kinetics of free carrier generation is investigated by the numerical
solution of the system of balance equations for particle concentrations within the multiband model of electron energy spectrum
of the crystal. It is shown that in the intensity range of 1010–1012 W/cm2 the proposed way of nonequilibrium carrier generation is more effective in the case of picosecond pulses than the conventional
multiphoton absorption. It is shown that the nonequilibrium carrier generation considered here may initiate a multiphoton
avalanche. 相似文献
950.
A correction factor accounting for the differences between the absorption spectra of an erythrocyte suspension and hemolyzed
blood (hemoglobin solution) has been calculated. Erythrocytes and their aggregates are simulated by “soft” cylindrical (disk-shaped)
particles. The anomalous diffraction approximation is used. At equal absorbing mass, the absorption coefficient of the suspension
in the blue spectral region is shown to be capable of being several times lower than that of the solution due to localization
of the absorber in erythrocytes. The hemoglobin localization effect is less important for λ
em
> 600 nm. Approximate analytical equations that are valid for cylindrical particles with a length-to-diameter ratio l/d >
3–4 are proposed for calculating the correction factor. More cumbersome formulas of anomalous diffraction must be used at
smaller l/d values. It is shown that these formulas transform at the limit into the analytical equations. The spectra of the
correction factor for cylindrical and spherical particles are compared. The simple approximation for spherical particles is
demonstrated to work well for rather long aggregates when the cylinder volume-to-surface area ratio is the same as for a spherical
particle. The results can be used to solve various problems of erythrocyte optics, e.g., to reproduce sizes of aggregates
by measuring their spectral absorption. 相似文献