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71.
P. G. Sennikov S. V. Golubev R. A. Kornev L. A. Mochalov A. A. Shilaev 《High Energy Chemistry》2014,48(1):49-53
The process of plasma-chemical conversion of silicon tetrafluoride in a radiofrequency (13.56 MHz) discharge has been studied. The dependence of the yield of silicon on the specific energy input and the H2/SiF4 molar ratio has been examined in the pressure range of 0.1–0.3 Tort. The maximum yield of silicon is 60%, and the optimal specific energy consumption is 44.6 MJ per mole of Si. A mechanism has been proposed for the plasma-assisted reduction of silicon tetrafluoride under the given experimental conditions. 相似文献
72.
M. Yu. Nikiforov V. A. Golubev G. M. Mamardashvili G. A. Al’per 《Journal of Structural Chemistry》2011,52(2):304-309
A method based on the statements of molecular association theory and a simple lattice model (ASL = Associated Solution + Lattice)
is used to calculate the solubility of a series of porphyrin macrocycles (blood porphyrins) in binary solvents (tetrachloromethane-ethyl
acetate, tetrachloromethane-methanol). Separate contributions to solubility are identified and the relative role of different
factors determining the solubility dependence on the mixed solvent composition is analyzed. The calculated solubility values
are in good agreement with the experimental data obtained for the studied systems by the isothermal saturation method with
a spectrophotometric control of concentrations. 相似文献
73.
E. V. Chernikova A. V. Morozov M. B. Kaziev E. S. Garina V. B. Golubev 《Polymer Science Series A》2007,49(9):962-974
The free-radical azeotropic bulk copolymerization of styrene and n-butyl acrylate at 90°C mediated by tert-butyl dithiobenzoate and copoly(strene—n-butyl acrylate) dithiobenzoate as reversible chain-transfer agents has been studied. It has been shown that low-and high-molecular mass chain-transfer agents allow one to efficiently control the molecular-mass characteristics of the copolymers. For all studied systems, the molecular mass linearly increases with conversion, and the copolymers are characterized by low polydispersity indexes. When polystyryl dithiobenzoate and poly(butyl acrylate) dithiobenzoate are used as polymer reversible chain-transfer agents in the azeotropic copolymerization of styrene and n-butyl acrylate, the diblock copolymers with the controlled block lengths are prepared. As evidenced by ESR studies, radical intermediates are formed in the course of the azeotropic copolymerization of styrene and n-butyl acrylate mediated by tert-butyl dithiobenzoate and the copolymer reversible chain-transfer agent; the kinetics of formation of these intermediates has been investigated. It has been demonstrated that the rate of the azeotropic copolymerization mediated by low-and high-molecular-mass reversible chain-transfer agents decreases with an increase in their concentration. The possible causes of this phenomenon are discussed. 相似文献
74.
The field evaporation of nickel, nichrome alloy, and tungsten carbide at different temperatures is studied with a time-of-flight atomic probe and a field emission microscope. The charge of evaporating ions does not depend on the emitter temperature: it decreases with decreasing evaporating field F ev. If F ev does not vary with temperature, so does the charge of the ions. In the case of multicomponent emitters with different ionization potentials of the components, the components evaporate at the same values of F ev in the form of atoms and ionized clusters. The reason for such behavior is that the initial evaporation of the easily ionizable component decreases the binding energy of harder-to-ionize ones to the point where they can evaporate at the same field. 相似文献
75.
Field emission methods are employed for studying the conditions of formation, crystallographic localization, and emissive
properties of preequilibrium thermofield microprotrusions for a number of refractory metals. Individual preequilibrium microprotrusions
can be easily obtained using a W emitter of the ordinary 〈110〉 orientation; however, the number of such protrusions on the
surface changes with time in the course of ionic emission, as well as their emission parameters (the parameters and the number
of microprotrusions do not change in the case of electron emission). Trihedral angles of the rearranged tip, which are formed
in the {111} regions, exhibit higher stability to ionic emission. A single trihedral angle stably emitting ions and located
on the geometrical axis of the emitter can easily be obtained with the help of a W emitter with the 〈111〉 orientation. Two
stable preequilibrium microprotrusions arranged symmetrically about the axis of the emitter in the {111} regions can be obtained
using a Ta emitter of the conventional 〈110〉 orientation. Such microprotrusions virtually do not change the emission parameters
during long-term extraction of ionic current. 相似文献
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