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S. F. Biagi M. Bourquin A. J. Britten R. M. Brown H. Burckhart A. A. Carter J. R. Carter Ch. Doré P. Extermann M. Gailloud C. N. P. Gee W. M. Gibson J. C. Gordon R. J. Gray P. Igo-Kemenes W. C. Louis T. Modis P. Mühlemann J. Perrier Ph. Rosselet B. J. Saunders P. Schirato H. W. Siebert V. J. Smith D. P. Stickland K. -P. Streit J. J. Thresher R. Weill 《Zeitschrift fur Physik C Particles and Fields》1981,9(4):305-314
Ξ ? interactions in hydrogen and deuterium are studied close to the forward direction using the CERN charged hyperon beam. The inclusive production of ∑*?(1385),Ξ ?,Ξ *0(1530),Ξ *?(1700),Ξ *?(1830), and Ω? is observed, as well as an enhancement in theΞ ?π+ channel at 1940 MeV/c2. The momentum distributions and the production cross sections are measured for ∑*?(1385),Ξ ?,Ξ *0(1530), and Ω?. 相似文献
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Beer L Britten JF Brusso JL Cordes AW Haddon RC Itkis ME MacGregor DS Oakley RT Reed RW Robertson CM 《Journal of the American Chemical Society》2003,125(47):14394-14403
New synthetic routes to 1,2,3-dithiazolo-1,2,3-dithiazolylium salts, based on double Herz condensations of N-alkylated 2,6-diaminopyridinium salts with sulfur monochloride, have been developed. The two prototypal 1,2,3-dithiazolo-1,2,3-dithiazolyl radicals HBPMe and HBPEt have been prepared and characterized in solution by cyclic voltammetry and EPR spectroscopy. Measured electrochemical cell potentials and computed (B3LYP/6-31G) gas-phase disproportionation enthalpies favor a low on-site Coulombic repulsion energy U in the solid state. The crystal structures of HBPR (R = Me, Et) have been determined by X-ray crystallography (at 293 K). Both consist of slipped pi-stacks of undimerized radicals, with many close intermolecular S- - -S contacts. Magnetic, conductivity, and optical measurements have been performed and the results interpreted in light of extended Hückel band calculations. The crystalline materials are paramagnetic above 100 K, with room-temperature conductivities sigma(RT) of 10(-5)-10(-6) S cm(-1); the slightly greater conductivity of the R = Et compound can be associated with a more well developed band structure. We suggest a Mott-Hubbard insulator ground state for these materials, with an on-site Coulomb repulsion energy U of about 1.0 eV. 相似文献
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John F Valliant Paul Schaffer Karin A Stephenson James F Britten 《The Journal of organic chemistry》2002,67(2):383-387
A nido-carborane analogue of tamoxifen, the widely employed breast cancer therapy agent, was prepared as an archetype of a potential new class of antiestrogen and boron neutron capture therapy agent in which the carborane is incorporated within the framework of the parent compound. The carborane was introduced through the reaction of 6,9-bis(acetonitrile)decaborane with a unique and highly conjugated ene-yne, which was prepared stereoselectively. NMR spectroscopy and a crystal structure of a key intermediate, the carborane analogue of chloro-tamoxifen, demonstrated the structural similarities between the tamoxifen carboranes and their corresponding phenyl analogues. 相似文献
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Laura E. HarringtonJames F. Britten Michael J. McGlinchey 《Tetrahedron letters》2003,44(44):8057-8060
The reaction of phenylethynyllithium with 9-bromofluorene yields 9,9′-bifluorenylidene, 8, 9,9′-bifluorenyl, 9, and a molecule 10, of formula C52H32, in which coupling has occurred between a 9,9′-bifluorenyl fragment and a 9,9′-bifluorenylidene moiety such that a C(9) position of the former is attached to a C(3) site of the latter. This parallels the unsymmetrical radical coupling of triphenylmethyl radicals, which leads to the Gomberg dimer, rather than hexaphenylethane. The structure of 10 has been elucidated by X-ray crystallography, and a mechanistic rationale is offered. 相似文献