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61.
L. A. Pesin S. S. Chebotaryov A. M. Kuvshinov I. I. Bespal’ I. V. Gribov N. A. Moskvina V. L. Kuznetsov S. E. Evsyukov A. V. Vyazovtsev N. S. Kravets 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2010,4(2):214-220
It has been studied how photoelectron and CKVV spectra of partially crystalline poly(vinylidene fluoride) (PVDF) are modified during a long-term degradation of its surface
under soft X-rays (AlK
α), which is accompanied by a flow of secondary electrons having different energies, and upon exposure to a unfocused beam
of 600 eV Ar+ ions. In both cases, the surface layer of the sample is enriched with carbon owing to defluorination. The shape of the electron
emission spectra of the carbonized layer depends on an external effect; that is, whether soft X-ray photons or ions are used
for defluorination. In the case of bombardment with Ar+, there is clear evidence for the dominance of the sp2 bonds between carbon atoms, as can be seen from the specific shape of the C KVV band and the C1s spectrum. The most surprising result of this study is that both photons and ions produce the same depth gradient of residual
fluorine at an equal fluorine concentration in the carbonized surface layer. The reason for this is not clear and needs further
investigation. 相似文献
62.
T. V. Murzina E. M. Kim R. V. Kapra O. A. Aktsipetrov M. V. Ivanchenko V. G. Lifshits S. V. Kuznetsova A. F. Kravets 《Physics of the Solid State》2005,47(1):153-155
This paper reports on the results of research into low-dimensional magnetic structures that have been intensively studied over previous decades due to the discovery of novel effects that are exhibited by these structures but not observed in bulk magnetic materials. A nonlinear optical analog of the magnetooptical Kerr effect is revealed in the optical third-harmonic generation in thin magnetic metallic films and nanogranular structures. It is shown that the magnetic nonlinear optical Kerr effect observed in the third harmonic exceeds the magnetooptical analog by more than one order of magnitude. 相似文献
63.
R.T. Mennicke D. Bozec V.G. Kravets M. VopsaroiuJ.A.D. Matthew S.M. Thompson 《Journal of magnetism and magnetic materials》2006
The Zhang–Levy–Granovskii (Z–L–G) model of the magnetorefractive effect (MRE) in granular films and the Jacquet–Valet (J–V) model, originally developed for magnetic multilayers, are compared and their common origin demonstrated. Simulations in an extended Hagen–Rubens (H–R) model give new insight into the variation with wavelength of the MRE, and the relative dependence of giant magnetoresistance (GMR) and the MRE to material and experimental parameters such as bulk and interface scattering parameters, mean free paths, grain diameter, polarisation and reflection geometry is explored. The sensitivity of the size, wavelength dependence and the position of the depth of the minimum in the MRE spectra to the different parameters is verified. We establish powerful new equations to correlate the MRE and GMR, and we analyse their validity for a variety of film parameters. This suggests a new approach to the use of the MRE in sensing GMR in the films. 相似文献
64.
Results of the study of optical and magneto-optical properties of MnSbBi(Pt, Co) films in a spectral region of 360–820 nm are reported. It is shown that the multilayer MnSbBi(Pt, Co) films obtained by magnetron sputtering possess considerable optical rotation in the geometry of the polar Kerr effect, which is as large as 0.5°–0.7° upon 5-h annealing of the films at 350°C. The spectral dependences measured for the magnitude of the polar Kerr effect showed that these films may be used for laser data recording in the short-wavelength spectral region, which substantially increases the recording density. Studies of the film structure by X-ray and electron diffraction analysis showed that the films have a polycrystalline structure, with granules 15–40 nm in size. Possible causes of a large magnitude of Kerr effect are analyzed. 相似文献
65.
V. G. Kravets 《Optics and Spectroscopy》2006,100(6):869-876
Magnetic-field induced changes revealed in reflectance spectra R(λ) of nonmagnetic dielectrics Al2O3, LiF, and MgO in the IR range (λ = 2.5–25 μm) are reported. The reflectance spectra are shown to have specific features in the vicinity of the wavelengths corresponding to optical phonon mode excitation in these crystals, with the magnetic field giving rise to a noticeable change of reflectance ΔR/R(λ) at these wavelengths. The value of ΔR/R(λ) for p-(s-) polarized IR radiation in a magnetic field of ~13 kOe is ~0.6% (~0.4%) for Al2O3 at λ ≈ 9.6 μm, ~1.63% (~1.15) for LiF at λ ≈ 11.1 μm, and ~ 0.07 (~0.2%) for MgO at λ ≈ 11.7 μm, respectively. These changes can be increased substantially by irradiating the dielectric crystals by x-ray radiation. It is shown that the optical and magnetooptical properties of the above dielectrics in the IR spectral region can be described in terms of the polaron excitation theory. 相似文献
66.
A. A. Artyukhov Ya. M. Kravets A. A. Artyukhov A. P. Babichev A. V. Ryzhkov 《Russian Journal of Inorganic Chemistry》2011,56(3):335-337
The reaction of carbon oxides and hydrogen in the presence of the Raney nickel catalyst has been used for water synthesis.
A procedure has been developed for the recovery and collection of the synthesized water with minimal losses and without deteriorating
the 17O or 18O isotope enrichment as compared to the initial CO2 and CO. The recovery of oxygen with high concentrations of 17O and 18O isotopes is based on the reaction of xenon difluoride with water. The yield based on oxygen achieves 99% without reduction
of isotope enrichment, which is confirmed by mass-spectral measurements of oxygen isotope concentrations in the initial reagents
and final reaction products. 相似文献
67.
A. A. Artyukhov Ya. M. Kravets A. A. Artyukhov A. E. Bryksin I. P. Gnidoi A. L. Ustinov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(8):1376-1379
A process for converting carbon monoxide to methane was developed. An apparatus with a productivity of ∼100 l per day was
created. Isotope-enriched methane with a low content of impurities (<10 ppm) was obtained. 相似文献
68.
É. Kh. Kravets S. S. Zlot-skii V. S. Martem'yanov D. L. Rakhmankulov 《Chemistry of Heterocyclic Compounds》1976,12(9):969-973
1,3-Dioxacyclanes are converted to esters in the presence of di-tert-butyl peroxide. The reaction is described by the kinetic equation of an unbranched chain reaction with quadratic chain termination. It is shown that five-membered acetals are more reactive than seven- and six-membered acetals. The introduction of hydrocarbon groups in the 2 position of the ring increases the reactivity. It is concluded that the primary site of attack by the alkyl radical is the methylene or methylidyne group adjacent to the two heteroatoms.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1171–1175, September, 1976. 相似文献
69.
70.
V. P. Perelygin Yu. V. Bondar R. Brandt W. Ensinger R. L. Fleischer L. I. Kravets M. Rebetez R. Spohr P. Vater S. G. Stetsenko 《Physics of Atomic Nuclei》2003,66(8):1569-1573
The main goal of the present work is the search for and identification of relatively stable nuclei of superheavy elements (SHE) (Z>110) in galactic matter by fossil track study of nonconducting crystals from the surface of meteorites and rocks from the lunar regolith. Nuclei of SHE are thought to be the products of nucleosynthesis in explosive processes in our Galaxy (supernova r-process nucleosynthesis and, especially, neutron-star formation, etc.). When accelerated to relativistic energies in the Galaxy, they can produce extended trails of damage in nonconducting extraterrestrial crystals. The lifetime of such SHE in galactic cosmic rays will range from 103 to 107 yr to be registered in extraterrestrial crystals. To search for and to identify the superheavy nuclei in the galactic cosmic rays, it was proposed to use the ability of nonconducting extraterrestrial crystals such as olivines, pyroxenes, and feldspars to detect and to store for many millions of years the trails of damage produced by fast Z≥23 nuclei coming to rest in the crystalline lattice. The track lengths of fast Z≥23 nuclei are directly proportional to Z2 of these nuclei. The nuclei of SHE produce, when coming to rest in a crystal volume, tracks that are a factor of 1.6–1.8 longer than the tracks due to cosmic-ray Th and U nuclei. To identify the tracks due to superheavy nuclei, calibrations of the same crystals were performed with accelerated Au, Pb, and U nuclei. For visualization of these tracks inside the crystal volume, proper controlled annealing and chemical etching procedures were developed. Since 1980, fossil tracks due to Th and U nuclei have observed and unambiguously identified (1988) by subsequent calibrations of the olivine crystals with accelerated U, Au, and Pb ions. The number of tracks of Th and U nuclei measured in olivine crystals totaled more than 1600, as compared with the prior 30 events. The other approach to identifying SHE in nature is to search for tracks in phosphate crystals from spontaneous fission of Z ≥ 110 nuclei; these produce two-prong and three-prong fission fragment tracks and differ significantly from the tracks from spontaneous fission of 238U and 244Pu nuclei. Extraterrestrial phosphate crystals of lunar and meteoritic origin will be investigated. Such SHE nuclei can survive in crystals of extraterrestrial rocks and produce spontaneous fission tracks, if the lifetime is more than 5×107 yr. 相似文献