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101.
S. Ramasamy D. J. Smith P. Thangadurai K. Ravichandran T. Prakash K. PAdmaprasad V. Sabarinathan 《Pramana》2005,65(5):881-891
The ultra high vacuum chamber was developed in the Department of Nuclear Physics, University of Madras with the funding from
DST, India. This UHV chamber is used to prepare nanocrystalline materials by inert gas condensation technique (IGCT). Nanocrystalline
materials such as PbF2, Mn2+-doped PbF2, Sn-doped In2O3 (ITO), ZnO, Al2O3, Ag2O, CdO, CuO, ZnSe:ZnO etc., were prepared by this technique and characterized. Results of some of these materials will be
presented in this paper. In solid-state207Pb NMR on PbF2 a separate signal due to the presence of grain boundary has been observed. The structural phase transition pressure during
the phase transformation from the cubic phase to orthorhombic phase under high pressure shows an increase with the decrease
in grain size. Presence of electronic centres in nanocrystalline PbF2 is observed from Raman studies and the same has been confirmed by photoluminescence studies. Al2O3 was prepared and56Fe ions were implanted. After implantation segregation of56Fe ions was examined by SEM. The oxidation properties of ITO were studied by HRTEM. As against the expectation of oxide coating
on individual nanograins of In-Sn alloy, ITO nanograins grew into faceted nanograins on heat treatment in air and O2 atmosphere. The growth of ITO under O2 atmosphere showed pentagon symmetry. The PMN was initially prepared by solid-state reaction. Further, this PMN relaxor material
will be used to convert into nanocrystalline PMN by IGCT with sputtering and will be studied 相似文献
102.
103.
Debadi Chakraborty Mohit Bajaj Leslie Yeo James Friend Matteo Pasquali J. Ravi Prakash 《ournal of non Newtonian Fluid Mechanics》2010,165(19-20):1204-1218
We compute the flow of three viscoelastic fluids (Oldroyd-B, FENE-P, and Owens blood model) in a two-dimensional channel partly bounded by a tensioned membrane, a benchmark geometry for fluid–structure interactions. The predicted flow patterns are compared to those of a Newtonian liquid. We find that computations fail beyond a limiting Weissenberg number. Flow fields and membrane shape differ significantly because of the different degree of shear thinning and molecular extensibility underlying the three different microstructural models. 相似文献
104.
K. Pradeesh Monika Agarwal K. Koteswara Rao G. Vijaya Prakash 《Solid State Sciences》2010,12(1):95-98
Quasi-one-dimensional lead (II) iodide compound, C14H18N2Pb2I6, with unique crystal structure was synthesized and solved for the crystal structure. These novel inorganic-organic hybrids have high thermal stability of upto 300 °C and show excitonic and charge-transfer features in their optical properties. An attempt has been made to understand the structural and optical mechanisms between inorganic one-dimensional polymeric PbI nano ribbons and the guest organic moiety for future applications in nanoscaled electronic devices. 相似文献
105.
Jai Prakash Jaiswal 《Acta Mathematica Hungarica》2011,132(4):358-366
The object of the present work is to obtain a necessary condition for the existence of weakly symmetric and weakly Ricci-symmetric
Sasakian manifolds admitting a quarter-symmetric metric connection. 相似文献
106.
107.
Joseph BK Verghese B Sudarsanakumar C Deepa S Viswam D Chandran P Asokan CV 《Chemical communications (Cambridge, England)》2002,(7):736-737
The conformational change induced by the introduction of a ketenedithioacetal moiety at C-4 of 1,7-substituted-1,6-heptadiene-3,5-diones results in favorable spatial relationships between the alkenoyl groups to effect efficient intramolecular cycloadditions: irradiation of bis(alkenoyl)ketenedithioacetals in solution leads to facile and stereospecific intramolecular [2 + 2] photocycloadditions resulting in the formation of substituted bicyclo[3.2.0]heptane-2,4-diones, the observed conformational rigidity of which is attributed to the push-pull character of the ketenedithioacetal group. 相似文献
108.
We provide experimental evidence for stretching and collapse of neutral polymer layers, already adsorbed at an oil-in-water interface, due to its interaction with surfactants. Upon stretching, the first interaction length (2L(0)) follows a power law dependence on surfactant concentration ( proportional, variant C(x)(s), where x approximately 0.5 for cationic surfactants) and collapses in the presence of salt, as a relatively weak power law (C(-y)(s), where y=0.17), in good agreement with brush length decay for polyelectrolyte brushes. 相似文献
109.
The electronic structure of substitutional non-magnetic impurities Cu, Ag, Cd, Mg, Zn, Ga, In, Ge, Si and Sn in Al is studied
using density functional theory. A simple physical model is proposed to calculate the effective charges on impurities in trivalent
metal Al. A linear relation is found between the effective charges on impurities and impurity vacancy capture radii. The spherical
solid model (SSM) is used to account for discrete nature of the host. The impurity-induced change in charge density, scattering
phase shifts, host-impurity potential, residual resistivity and impurity self-energy are calculated. Higher order scattering
phase shifts are found significant and the host-impurity potential is found proportional to effective charge on impurity in
its vicinity. The self-consistently calculated potential is used to calculate the electric field gradients (EFGs) at the first
and second nearest neighbours (1NNs, 2NNs) of impurity. The calculated values are in agreement with the experimental results. 相似文献
110.
V. K. Gupta S. K. Badval I. K. Daftari G. L. Kaul L. K. Mangotra N. K. Rao S. K. Sharma Gian Singh Y. Prakash 《Zeitschrift fur Physik C Particles and Fields》1981,10(1):29-36
The shower particle multiplicity (〈n s 〉) in thep-nucleus interactions for different targets, in the incident energy range of ~6–500 GeV has been studied. The variation of multiplicity parameters with target mass (A) or with number of interactions that the incident hadron suffers inside the nucleus (v A ) and with the changed particle multiplicity inp-p interactions (〈n ch〉) has been examined in the light of the various models of multiparticle production. The present analysis favours the hydrodynamical model though some other models can not be conclusively ruled out. 相似文献