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201.
Alexander V. Arkhipov Oleg I. Belous Boris M. Bulgakov Anatoliy I. Fisun 《International Journal of Infrared and Millimeter Waves》2002,23(3):507-516
Experimental investigations of quasi-optical power combiner based on a half-open resonator are described. Power and frequency characteristics have been studied for one or three diodes. It is shown that the positioning of the diodes is preferred over the center of the field spot along a resonator axis. 相似文献
202.
Lucio Forni Vitalii Y. Tugarinov Francesco P. Vatti Cesare Oliva Anatolii V. Vishnyakov 《Reaction Kinetics and Catalysis Letters》1993,49(2):271-278
Desorption activation energy of both reactants and products was found to be only slightly higher than the desorption enthalpy and, for reactants, it was higher than the activation energy for the title reaction. Methylpyrazine desorbs much more easily than reactants. 相似文献
203.
Summary Gypsogenic acid, previously obtained by the oxidation of gypsogenin and hederagenin, has been found for the first time inA. subglabrum andA. gypsophiloides.Khimiya Prirodnykh Soedinenii, Vol. 3, No. 2, pp. 95–97, 1967 相似文献
204.
A. G. Belous O. Z. Yanchevskii A. V. Kramarenko 《Russian Journal of Applied Chemistry》2006,79(3):345-350
Rounded nanosize particles of Co3O4 and NiO were prepared by precipitation with ammonium carbonate from cobalt and nickel nitrate solutions. Cobalt and nickel oxides and their precursors were characterized by thermal and X-ray phase analyses, electron microscopy, and IR spectroscopy. 相似文献
205.
A significant activation of the Ctbd1;N group in organonitriles upon their coordination to a platinum(IV) center has been found in the reaction of [PtCl(4)(RCN)(2)] (R = Me, Et, CH(2)Ph) with the nitrile oxides 2,4,6-R'(3)C(6)H(2)CNO (R' = Me, OMe) to give the (1,2,4-oxadiazole)platinum(IV) complexes (R = Me, R' = Me (1); R = Et, R' = Me (2); R = Et, R' = OMe (3); R = CH(2)Ph, R' = Me (4)); the [2 + 3] cycloaddition was performed under mild conditions (unless poor solubility of [PtCl(4)(RCN)(2)] precludes the reaction) starting even from complexed acetonitrile and propionitrile, which exhibit low reactivity in the free state. The reaction between complexes 2-4 and 1 equiv of Ph(3)P=CHCO(2)Me in CH(2)Cl(2) leads to the appropriate platinum(II) complexes (5-7); the reduction failed only in the case of 1 insofar as this complex is insoluble in the most common organic solvents. All the platinum compounds were characterized by elemental analyses, FAB mass spectrometry, and IR and (1)H, (13)C((1)H), and (195)Pt NMR spectroscopies, and three of them also by X-ray crystallography. The oxadiazoles formed in the course of the metal-mediated reaction were liberated almost quantitatively from their Pt(IV) complexes by reaction of the latter (complexes 2-4) with an excess of pyridine in chloroform, giving free 1,2,4-oxadiazoles and trans-[PtCl(4)(pyridine)(2)]; the sequence of the Pt(IV)-mediated [2 + 3] cycloaddition and the liberation opens up an alternative route for the preparation of this important class of heterocycles. 相似文献
206.
207.
208.
Michail N. Elinson Sergey K. Feducovich Anatolii N. Vereshchagin Sergey V. Gorbunov Pavel A. Belyakov Gennady I. Nikishin 《Tetrahedron letters》2006,47(51):9129-9133
Electrolysis of an aldehyde, malononitrile and a malonate in an alcohol in an undivided cell in the presence of sodium acetate-sodium halide as a double mediatory system results in the formation of 3-substituted-2,2-dicyanocyclopropane-1,1-dicarboxylates in 40-60% yields. 相似文献
209.
To develop a numerical solution of mentioned equations the method of factorized projection of integral operator kernel is applied. All matrix elements of the method are calculated analytically, being expressed in terms of two types of standard integrals: the overlap integrals and one-electron Coulomb integrals. To calculate the integrals we used the O(4)-symmetry of hydrogen-like atomic orbitals as well as operational technique of differentiation with respect to scalar and vector parameters. 相似文献
210.
Herrero CP Varez A Rivera A Santamaría J León C V'yunov O Belous AG Sanz J 《The journal of physical chemistry. B》2005,109(8):3262-3268
Influence of the vacancy concentration on the Li conductivity of the (Li(1-x)Na(x))(0.2)La(0.6)TiO(3) and (Li(1-x)Na(x)(0.5)La(0.5)TiO(3) perovskite series, with 0 < or = x < 1, has been investigated by neutron diffraction (ND), impedance spectroscopy (IS), nuclear magnetic resonance (NMR), and Monte Carlo simulations. In both series, Li(+) ions occupy unit cell faces, but Na(+) ions are located at A sites of the perovskite. From this fact, the amount of vacant A sites that participate in Li conductivity is given by the expression n(v) = [Li] + square, where square is the nominal vacancy concentration. Substitution of Li by Na decreases the amount of vacancies, reducing drastically the Li conductivity when n(v) approaches the percolation threshold of the perovskite conduction network. In disordered (Li(1-x)Na(x))(0.5)La(0.5)TiO(3) perovskites, the percolation threshold is 0.31; however, in ordered (Li(1-x)Na(x))(0.2)La(0.6)TiO(3) perovskites, this parameter changes to 0.26. Near the percolation threshold, the amount of mobile Li species deduced by (7)Li NMR spectroscopy is lower than that derived from structural formulas but higher than deduced from dc conductivity measurements. Conductivity values have been explained by Monte Carlo simulations, which assume a random walk for Li ions in the conduction network of the perovskite. In these simulations, distribution of vacancies conforms to structural models deduced from ND experiments. 相似文献