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81.
V. I. Boiko V. V. Evstigneev N. N. Prilepskikh I. V. Shamanin 《Russian Physics Journal》1986,29(6):437-440
Relations describing the process of heat transfer from the energy-dissipation region of a monoenergetic ion beam in an obstructing target within the pulse duration are derived on the basis of an analysis of the fundamental laws governing the interaction of a high-intensity ion beam with condensed media and the solution of the heat-conduction equation. The proposed analytical expressions can be used to assess the feasibility of neglecting thermal conductivity and calculating the temperature fields in the target without solving the heat-conduction boundary-value problem, namely on the basis of the characteristics of a heat-release source approximating the real source.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 16–20, June, 1986. 相似文献
82.
Entropy and Random Vectors 总被引:1,自引:0,他引:1
Barron(1) produced a proof of the Central Limit Theorem for real-valued IID random variables, in the sense of convergence in relative entropy. Here, we establish a similar result for independent real-valued random vectors, not necessarily identically distributed. The main developments required are a generalisation of De Bruijn's identity, and various inequalities proposed in ref. 2. 相似文献
83.
84.
Specific features of the melting of PET samples with different molecular masses after their thermal and mechanical treatment
(orientational drawing) are studied by the DSC method. Orientational drawing of the samples leads to the development of a
supermolecular structure, which depends on the molecular mass and thermal prehistory of the initial samples. 相似文献
85.
86.
87.
ABSTRACTHigh sensitivity of liquid crystals to the electric field makes them highly demanded and widely used in different applications. Despite the large number of the electro-optical research on the low-molar-mass liquid crystals electro-optics of the liquid crystalline (LC) polymers is much less studied. Herein, the comparative electro-optical behaviour of two nematic comb-shaped polyacrylates with phenylbenzoate mesogenic side groups was studied in detail. These two polyacrylates have completely the same structure of polymer backbone and spacer length but different in the direction of the ester group in the phenylbenzoate fragments. It was found that this difference predetermines their completely opposite electro-optical properties.The influence of the electric field of different strength and frequency on the orientation of the mesogenic groups of these polymers is studied. It is shown that application of the electric field at temperatures above the glass transition temperature (~25°C) induces reorientation of the mesogenic groups along or perpendicular to the electric field direction depending in its turn on the ester group direction. For one of the polyacrylates an unusual textural transition is found; during cooling of the polymer sample under applied field at definite temperature a sharp change in the mesogen’s orientation from homeotropic to planar one is found. This electro-optical phenomenon is observed for the first time and probably associated with sharp change in sign of anisotropy of dielectric permittivity from positive (at high temperatures) to negative one (at lower temperatures). Kinetics of the electro-optical switching at different temperatures, influence of the molar masses of the polymer and frequency of the applied AC field on electro-optical behaviour of the polymers are studied. The possibility of the fixation of the electroinduced homeotropic alignment of the mesogenic groups by photopolymerisation of the diacrylate dissolved in the polymer is demonstrated. 相似文献
88.
The method proposed in [1, 2] is used to construct an analytic solution of the problem of two incompressible plates propelled by the explosion products of a condensed explosive. A solution of the problem by the classical methods of the gas dynamics of a perfect gas with =3 was previously obtained in [3]. However, the analysis carried out in [3] does not reproduce the entire wave configuration which may result from the interaction of expansion waves with moving plates and is limited to the study of the flow configuration realized in the case of single reflection of the waves from the plate contact boundary. This leads to overestimation of the limiting projection velocities when the relative masses of the plates are greater than unity.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 148–152, March–April, 1991. 相似文献
89.
Yuri M. Boiko 《Journal of Polymer Science.Polymer Physics》2010,48(18):2012-2021
A lap‐shear joint mechanical testing method has been probed to measure the surface glass transition temperature (T) of the thick bulk films of high‐molecular‐weight polymers. As T, the temperature transition “occurrence of autoadhesion–nonoccurrence of autoadhesion” has been proposed. The influence of chain flexibility, of molecular architecture, of polymer morphology, and of chain ends concentration on the T has been investigated. The correlation between the reduction in T with respect to the glass transition temperature of the bulk (T) and the intensity of the intermolecular interaction in the polymer bulk in amorphous polymers has been found. The effect of surface roughness on T has been discussed. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 2012–2021, 2010 相似文献
90.
Alexey Lipatov Alexander Gribanov Andriy Grytsiv Peter Rogl Yurii Seropegin 《Journal of solid state chemistry》2010,183(4):829-6521
Phase relations have been established in the ternary system Ce-Rh-Si for the isothermal section at 800 °C based on X-ray powder diffraction and EPMA on about 80 alloys, which were prepared by arc melting under argon or by powder reaction sintering. From the 25 ternary compounds observed at 800 °C 13 phases have been reported earlier. Based on XPD Rietveld refinements the crystal structures for 9 new ternary phases were assigned to known structure types. Structural chemistry of these compounds follows the characteristics already outlined for their prototype structures: τ7—Ce3RhSi3, (Ba3Al2Ge2-type), τ8—Ce2Rh3−xSi3+x (Ce2Rh1.35Ge4.65-type), τ10—Ce3Rh4−xSi4+x (U3Ni4Si4-type), τ11—CeRh6Si4 (LiCo6P4-type), τ13—Ce6Rh30Si19.3 (U6Co30Si19-type), τ18—Ce4Rh4Si3 (Sm4Pd4Si3-type), τ21—CeRh2Si (CeIr2Si-type), τ22—Ce2Rh3+xSi1−x (Y2Rh3Ge-type) and τ24—Ce8(Rh1−xSix)24Si (Ce8Pd24Sb-type). For τ25—Ce4(Rh1−xSix)12Si a novel bcc structure was proposed from Rietveld analysis. Detailed crystal structure data were derived for τ3—CeRhSi2 (CeNiSi2-type) and τ6—Ce2Rh3Si5 (U2Co3Si5-type) by X-ray single crystal experiments, confirming the structure types. The crystal structures of τ4—Ce22Rh22Si56, τ5—Ce20Rh27Si53 and τ23—Ce33.3Rh58.2−55.2Si8.5−11.5 are unknown. High temperature compounds with compositions Ce10Rh51Si33 (U10Co51Si33-type) and CeRhSi (LaIrSi-type) have been observed in as-cast alloys but these phases do not participate in the phase equilibria at 800 °C. 相似文献