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41.
Abstract— Enhanced reactivation of UV- and y-irradiated herpes virus was investigated by the plaque assay onCV–1 monkey kidney monolayer cells irradiated with UV light or X-rays. Both UV- and X-irradiatedCV–1 cells showed enhancement of survival of UV-irradiated virus, while little or no enhancement was detected for y-irradiated virus assayed on UV- or X-irradiated cells. The enhanced reactivation of UV-irradiated virus was greater when virus infection was delayed 24 or 48 h, than for infection immediately following the irradiation of cells. It is demonstrable that the UV- or X-irradiatedCV–1 cells are able to enhance the repair of UV damaged herpes virus DNA, but not of y-ray damaged ones. 相似文献
42.
Ohgaki K Nakatsuji K Takeya K Tani A Sugahara T 《Physical chemistry chemical physics : PCCP》2008,10(1):80-82
Electron spin resonance measurement of gamma-ray-irradiated propane hydrates shows that the normal propyl radical withdraws hydrogen from the adjacent propane molecule through the hexagonal planes of the hydrate cage without water molecule bridging. 相似文献
43.
The preparation and pyrolysis of a blended precursor possessing Ti? N and Al? N bonds were investigated. The precursor was prepared by mixing (HAlN iPr) n, whose main compo‐nent was a cage‐type compound, and an aminolysis product of Ti(NMe2)4 with MeHNCH2CH2NHMe with a molar ratio of Ti:Al = 2:1. IR analysis of the products pyrolyzed under NH3–N2 indicated that a large proportion of the organic groups in the precursor were removed by an amine‐exchange reaction during the pyrolysis under NH3; thus, the products contained only a small amount of carbon. On the contrary, a considerable amount of carbon was present in the product pyrolyzed under Ar. Composites consisting of AlN and an NaCl‐type compound were obtained after pyrolysis of the precursor under both NH3–N2 and Ar. The composition of the NaCl‐type compound depended significantly on the pyrolysis atmosphere. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
44.
Sugahara T Kobayashi Y Tani A Inoue T Ohgaki K 《The journal of physical chemistry. A》2012,116(10):2405-2408
To investigate the molecular interaction between guest species inside of the small and large cages of methane + propane mixed gas hydrates, thermal stabilities of the methyl radical (possibly induced in small cages) and the normal propyl and isopropyl radicals (induced in large cages) were investigated by means of electron spin resonance measurements. The increase of the total amount of the normal propyl and isopropyl radicals reveals that the methyl radical in the small cage withdraws one hydrogen atom from the propane molecule enclathrated in the adjacent large cage of the structure-II hydrate. A guest species in a hydrate cage has the ability to interact closely with the other one in the adjacent cages. The clathrate hydrate may be utilized as a possible nanoscale reaction field. 相似文献
45.
Keiichi Kato Norio Koine Yoshiyuki Imai Koichi Akiyama Takuya Sugahara 《Journal of Dispersion Science and Technology》2013,34(8):1217-1222
The molecular compositions of the commercial nonionic surfactants Span 80 and Span 85 were analyzed by reversed phase high performance liquid chromatography (HPLC). Both surfactants are mixtures of fatty acid esters, containing monoesters, diesters, triesters, and tetraesters. While diesters dominate in the case of Span 80, Span 85 contains mainly tetraesters. Vesicles were prepared from Span 80 (or Span 85) by a two‐step emulsification method that involved homogenization and separation steps in which a portion of the surfactants was removed. The composition of the vesicles was analyzed by HPLC with respect to the different esters present. Although commercial Span 80 and Span 85 differ considerably in their molecular compositions, the ester profiles of the vesicles formed were in both cases rather similar and dominated by diesters. Therefore, the particular vesicle preparation method leads to a molecular selection of mainly those components that are prone to form bilayers. 相似文献
46.
Sugahara K Kitamura Y Murata M Satake M Tachibana K 《The Journal of organic chemistry》2011,76(9):3131-3138
A polyoxy linear carbon chain compound, prorocentrol (1), was isolated from cultured cells of the dinoflagellate Prorocentrum hoffmannianum, which produces a polyether carboxylic acid, okadaic acid. The structure of 1 was elucidated by detailed analyses of 2D NMR spectra. Compound 1 possesses 30 hydroxy groups, 1 ketone, and 8 double bonds on the C65-linear carbon chain. Its partial relative configuration was deduced by the proton-proton and long-range carbon-proton coupling constants, and compound 1 showed moderate cytotoxicity and antidiatom activity. 相似文献
47.
Kamata K Sugahara K Yonehara K Ishimoto R Mizuno N 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(27):7549-7559
A divanadium‐substituted phosphotungstate, [γ‐PW10O38V2(μ‐OH)2]3? ( I ), showed the highest catalytic activity for the H2O2‐based epoxidation of allyl acetate among vanadium and tungsten complexes with a turnover number of 210. In the presence of I , various kinds of electron‐deficient alkenes with acetate, ether, carbonyl, and chloro groups at the allylic positions could chemoselectively be oxidized to the corresponding epoxides in high yields with only an equimolar amount of H2O2 with respect to the substrates. Even acrylonitrile and methacrylonitrile could be epoxidized without formation of the corresponding amides. In addition, I could rapidly (≤10 min) catalyze epoxidation of various kinds of terminal, internal, and cyclic alkenes with H2O2 under the stoichiometric conditions. The mechanistic, spectroscopic, and kinetic studies showed that the I ‐catalyzed epoxidation consists of the following three steps: 1) The reaction of I with H2O2 leads to reversible formation of a hydroperoxo species [γ‐PW10O38V2(μ‐OH)(μ‐OOH)]3? ( II ), 2) the successive dehydration of II forms an active oxygen species with a peroxo group [γ‐PW10O38V2(μ‐η2:η2‐O2)]3? ( III ), and 3) III reacts with alkene to form the corresponding epoxide. The kinetic studies showed that the present epoxidation proceeds via III . Catalytic activities of divanadium‐substituted polyoxotungstates for epoxidation with H2O2 were dependent on the different kinds of the heteroatoms (i.e., Si or P) in the catalyst and I was more active than [γ‐SiW10O38V2(μ‐OH)2]4?. On the basis of the kinetic, spectroscopic, and computational results, including those of [γ‐SiW10O38V2(μ‐OH)2]4?, the acidity of the hydroperoxo species in II would play an important role in the dehydration reactivity (i.e., k3). The largest k3 value of I leads to a significant increase in the catalytic activity of I under the more concentrated conditions. 相似文献
48.
Takashi Makino Yoshihiro Ogura Yuuki Matsui Takeshi Sugahara Kazunari Ohgaki 《Fluid Phase Equilibria》2009
The isothermal phase equilibria of the carbon dioxide + cyclopropane mixed-gas hydrate system were investigated by means of static temperature measurement and Raman spectroscopic analysis. Raman spectra indicated that the crystal structure of the carbon dioxide + cyclopropane mixed-gas hydrate changes from structure-I to structure-II and back to structure-I with an increase of the equilibrium carbon dioxide composition at 279.15 K, while each simple gas hydrate belongs to structure-I at the temperature. Whereas, unlike 279.15 K, no structural phase transition occurs along the isothermal stability boundary at 284.15 K. 相似文献
49.
A precursor prepared from a methyltriethoxysilane ((CH3)Si(OC2H5)3, MTES)-B(OC2H5)3-polyacrylonitrile (PAN) composition was used for the synthesis of boron-doped SiC by carbothermal reduction. Initially, MTES was hydrolyzed with HCl (MTES: H2O: HCl = 1 : 1 : 0.01) for 1 h in a sealed vessel. The number-average molecular weight measurement and a NMR spectrum revealed that the species in the solution were mainly oligometric. With the addition of B(OC2H5)3, no significant changes in the distribution of the Si containing species were detected. The mixing of the hydrolyzed solution with a PAN-dimethylsulfoxide solution led to a homogeneous solution. After the evaporation of the solvents and the subsequent heat treatment at 220° C, brown precursor powder was obtained. By the heat treatment at 1600° C in Ar, it was converted to boron-doped SiC powder. 相似文献
50.
The vortex-lattice melting transition in Bi(2)Sr(2)CaCu(2)O(8 + delta) single crystals was studied using in-plane resistivity measurements in magnetic fields tilted away from the c axis to the ab plane. In order to avoid the surface barrier effect which hinders the melting transition in the conventional transport measurements, we used the Corbino geometry of electric contacts. The complete H(c) - H(ab) phase diagram of the melting transition in Bi(2)Sr(2)CaCu(2)O(8 + delta) is obtained for the first time. The c-axis melting field component H(c)(melt) exhibits the novel, stepwise dependence on the in-plane magnetic fields H(ab) which is discussed on the basis of the crossing vortex-lattice structure. The peculiar resistance behavior observed near the ab plane suggests the change of phase transition character from first to second order. 相似文献