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101.
102.
Summary Complete active space SCF, CASSCF, and contracted CI calculations have been performed on the -bonded complex between ethylene and an iron atom. An extended basis set of the ANO type was used, which included polarization functions on all centers. The results indicate an attractive interaction between Fe 5
F(d7s) and ethylene, with an estimated binding energy of 14 kcal/mol. The low spin complex arising from Fe 3
F(d7s) was found to be bound with 18 kcal/mol. Both these potential minima are, however, above the ground state of the iron atom. It is concluded that the interaction between atomic ground state iron and ethylene is not of the normal -bonded type, but is dominated by dispersion forces. A preliminary study showed this interaction to be almost isotropic, with no preferred site for the iron atom. 相似文献
103.
Per Kofstad 《Journal of Physics and Chemistry of Solids》1983,44(2):129-133
A method for studying metal ion self-diffusion in oxides (or other inorganic compounds) is described. The method involves oxidation of an appropriate metal to form a dense, single-layered scale of the lowest valent oxide (e.g. MnO on Mn). The specimen is then treated in high vacuum, and the evaporation of metal diffusing through the scale is measured. From the rates of metal diffusion/evaporation as a function of scale thickness information about the defect structure is obtained. The metal ion self-diffusion coefficient is determined from the rate of metal transport (evaporation) through a scale with known thickness. The requirements and limitations of the method are discussed. The use of the method is illustrated for Mn self-diffusion in MnO at 1100°C. The self-diffusion coefficient of Mn in MnO is proportional to the square root of the oxygen pressure, , in t MnO phase field near the MnO/Mn3O4 phase boundary. It is also tentatively concluded that the predominating defects near the Mn/MnO phase boundary are manganese interstitials. 相似文献
104.
The form of the nonrigid bender has changes that here we do render. We add, nicely paired, a term to J2 and regroup factors that are singular. As a result, the nonrigid bender Hamiltonian can now be set up using only Van Vleck perturbation theory, for any triatomic molecule (linear, quasi-linear, or bent). It can be used to calculate the rotation-vibration energies of the molecule to high from the bending potential energy function and the stretch and stretch-bend force constants. 相似文献
105.
Herein we describe the design, synthesis, and solution structure of a novel type of conjugate composed of a naturally occurring bio-active ligand bound to an artificial peptidomimetic backbone; in this first report on such functionalized foldamers we utilized a beta-peptide as backbone and a GalNAc carbohydrate residue as ligand. 相似文献
106.
Vogt U Lindblom M Jansson PA Tuohimaa TT Holmberg A Hertz HM Wieland M Wilhein T 《Optics letters》2005,30(16):2167-2169
We report on a compact interferometer for the water-window soft-x-ray range that is suitable for operation with laser-plasma sources. The interferometer consists of a single diffractive optical element that focuses impinging x rays to two focal spots. The light from these two secondary sources forms the interference pattern. The interferometer was operated with a liquid-nitrogen jet laser-plasma source at lambda=2.88 nm. Scalar wave-field propagation was used to simulate the interference pattern, showing good correspondence between theoretical and experimental results. The diffractive optical element can simultaneously be used as an imaging optic, and we demonstrate soft-x-ray microscopy with interferometric contrast enhancement of a phase object. 相似文献
107.
108.
Bromine-lithium exchange using tert-butyllithium at -78 degrees C initiates a cascade process whereby either xanthone derivatives or pentacyclic 13-azadibenzo[a,de]anthracenes are produced in high yields. The reaction proceeds via a sequential intramolecular trapping of organolithium intermediates. 相似文献
109.
Pretreatment of polystyrene beads with a nonpolar organic solvent is the key for the generation of mechanically robust tablets consisting of neat functionalized polystyrene beads, both alone and in combination with solid reagents or catalysts. The novel dosing methodology provides accurately preweighed tablets in virtually any shape and size and with excellent disintegration properties, speeding up parallel solution and solid phase synthesis. The use of tablets is demonstrated in parallel Mitsunobu and acylation reactions. 相似文献