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101.
A new method of synthesis of acetic acid in water has been developed from the carboxylation of methane with carbon monoxide using lanthanide catalysts. Ytterbium(III) acetate has been found to be the most active catalyst among the compounds of the lanthanide series in the carboxylation reaction of methane with carbon monoxide. Sodium hypochlorite or hydrogen peroxide was used as the oxidant in this reaction. Sodium hypochlorite exhibited more favorable activity than hydrogen peroxide in the reaction. The catalytic activity was improved by the addition of transition-metal salts such as manganese(II) acetate. The best result has been found at a ratio of manganese(II) acetate to ytterbium(III) acetate of 1:10. The optimum reaction conditions (reaction temperature, 40 °C; time, 20 h; methane, 20 atm; carbon monoxide, 5 atm) have been obtained. © 1998 John Wiley & Sons, Ltd. 相似文献
102.
103.
As a complementary scheme to a coupling-hole type laser, a walk-off ring coupling type laser is proposed to extract a donut shaped beam by shrinking the diameter of one of the stable resonator mirrors. This was successfully applied to a conventional slow axial-flow CO laser. First, finding the intensity distribution close to the Gaussian profile by using a partially transparent mirror in a hemispherical configuration for coupling, we obtain the relationship between the mirror radius and the effective transmittance. Then, using several mirrors with a diameter smaller than the Gaussian profile above instead of the partially transparent mirror, the output power with the donut shape was optimized to yield the maximum power, together with theoretical treatments. This resulted in an optimum mirror diameter of 4.2 mm, which corresponds to the optimum transmittance of 5-6% for the CO laser having the gain parameter G≅0.34, the inherent loss ā ≅ 0.07, and the measure of partial homogeneity m¯ =; 0.5. This value is exactly the same as that of the coupling-hole mirror. Some application feasibilities are also discussed. 相似文献
104.
Norio Ishizuka Kazuki Nakanishi Kazuyuki Hirao Nobuo Tanaka 《Journal of Sol-Gel Science and Technology》2000,19(1-3):371-375
Continuous macroporous silica gel networks were prepared in a fused silica capillary, and evaluated in reversed-phase liquid chromatography. Under pressure-driven conditions, considerable dependence of column efficiency on the linear velocity of the mobile phase was observed in spite of the small size of the silica skeletons. A major source of band broadening in the pressure-driven mode was found in the A-term of van Deemter equation. The performance of the continuous silica capillary column in the electro-driven mode was much better than that in the pressure-driven mode. 相似文献
105.
Masahide Senoo Yuzo Kotani Masami Kamigaito Mitsuo Sawamoto 《Macromolecular Symposia》2000,157(1):193-200
RuCl2(PPh3)3 led to living radical copolymerization of N,N‐dimethylacrylamide (DMAA) and methyl methacrylate (MMA) in conjunction with a halide‐initiator (R‐X; CHCl2COPh, CCl3Br) and Al(Oi‐Pr)3 in toluene at 80°C. Both the monomers were polymerized at almost the same rate into random copolymers, where the number‐average molecular weights (Mn) increased in direct proportion to weight of the obtained polymers, and the molecular weight distributions (MWDs) were narrow throughout the reactions (Mw/Mn = 1.2‐1.6). MMA was consumed faster in the copolymerization than in the homopolymerization, which was due to the interaction of DMAA with the ruthenium complex. The Ru(II)‐based initiating system was also effective in block copolymerization of DMAA and MMA. 相似文献
106.
Hideji Komatsu Ryoji Mogi Michio M. Matsushita Tadashi Miyagi Yuzo Kawada Tadashi Sugawara 《Polyhedron》2009,28(9-10):1996-2000
A novel organic donor radical, TSBN, which is a benzotetraselenafulvalene derivative carrying a nitronyl nitroxide group in a cross-conjugated manner was prepared. X-ray crystallographic analysis revealed that TSBN forms a sheet-like network within the ac plane through intermolecular chalcogen contacts. Its spin-polarized structure was confirmed by cyclic voltammogram, ESR spectra of singly oxidized species and DFT calculation. The neutral crystal of TSBN showed nonlinear I–V characteristics at 2 K and exhibited negative magnetoresistance (?5% at 2 K under 5 T). 相似文献
107.
108.
Norio Tsujioka Norio Ishizuka Nobuo Tanaka Takuya Kubo Ken Hosoya 《Journal of polymer science. Part A, Polymer chemistry》2008,46(10):3272-3281
We recently presented a short communication on the preparation of epoxy‐based monoliths possessing highly ordered structures by polymerization induced phase separation based on the spinodal decomposition. In this article, we describe in detail on reaction mechanisms and structural properties of the epoxy‐based monoliths with well‐controlled macropores in the micrometer range. We prepared epoxy‐based monoliths based on diglycidyl ether of bisphenol A, bis(4‐aminocyclohexyl)methane, and polyethylene glycol with a bicontinuous structure by in situ step‐growth polymerization. Different morphology of epoxy‐based monoliths could be obtained by changing formulation of monomers and porogenic solvents. Characterizations of their morphologies were performed using scanning electron microscopy, mercury intrusion porosimetry, small angle X‐ray scattering, and gas adsorption measurement (BET method). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3272–3281, 2008 相似文献
109.
110.
Both enantiomers of the title compounds were synthesized and the crystal structure of one of them was determined by X-ray crystallography. The indole Grignard reaction was effective for synthesizing the key intermediate of the (R)-isomers. The analgesic activities of the products were compared with those of 4-methylaminomethyl-2,3,4,9-tetrahydrothiopyrano[2,3-b]indole (1), Isoxal, and Tiaramide. The (R)-isomers were more potent than the corresponding (S)-isomers, and were more potent than Isoxal and Tiaramide, but less potent than 1. 相似文献