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41.
Yoshinori Takano Yuichiro Kashiyama Nanako O. Ogawa Yoshito Chikaraishi Naohiko Ohkouchi 《Rapid communications in mass spectrometry : RCM》2010,24(16):2317-2323
We have established a procedure for removing interfering materials from extracts of geological and biological samples, in order to determine precise compound‐specific nitrogen isotopic compositions of amino acids. We employed cation‐exchange chromatography of protein and non‐protein amino acids prior to derivatization for gas chromatographic separation. The average recovery of a standard amino acid solution was better than 94%, without nitrogen isotope fractionation during the cation‐exchange chromatography. We applied the procedure to various environmental samples including ‘hard’ (calcareous, siliceous, rock and sediment samples) and ‘soft’ materials (aggregated microbial samples and biological soft tissue samples). We conclude that cation‐exchange chromatography is a pre‐treatment procedure which should be widely useful for the determination of compound‐specific nitrogen isotopic compositions of amino acids. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
42.
Dr. Kojiro Fuku Honami Kanai Masanobu Todoroki Nanako Mishima Taisei Akagi Dr. Takashi Kamegawa Prof. Naoki Ikenaga 《化学:亚洲杂志》2021,16(14):1887-1892
Water pollution derived from organic pollutants is one of the global environmental problems. The Fenton reaction using Fe2+ as a homogeneous catalyst has been known as one of clean methods for oxidative degradation of organic pollutants. Here, a layered double hydroxide (Fe2+Al3+-LDH) containing Fe2+ and Al3+ in the structure was used to develop a “heterogeneous” Fenton catalyst capable of mineralizing organic pollutants. We found that sulfate ion (SO42−) immobilized on the Fe2+Al3+-LDH significantly facilitated oxidative degradation (mineralization) of phenol as a model compound of water pollutants to carbon dioxide (CO2) in a heterogeneous Fenton process. The phenol conversion and mineralization efficiency to CO2 reached >99% and ca. 50%, respectively, even with a reaction time of only 60 min. 相似文献
43.
Gesa Schfer Jelena Mili Adeeb Eldahshan Frank Gtz Kerstin Zühlke Christian Schillinger Annika Kreuchwig Jonathan M. Elkins Kamal R. AbdulAzeez Andreas Oder Marie C. Moutty Nanako Masada Monika Beerbaum Brigitte Schlegel Sylvia Niquet Peter Schmieder Gerd Krause Jens Peter vonKries Dermot M. F. Cooper Stefan Knapp Jrg Rademann Walter Rosenthal Enno Klussmann 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2013,125(46):12409-12413
44.
Takashi Fukutomi Hiroki Oomori Yoshibumi Sugito 《Journal of polymer science. Part A, Polymer chemistry》1996,34(13):2729-2735
Poly(methyl methacrylate) microgels covered with poly(hydroxyethyl methacrylate) thin layer was dispersed in poly(vinyl alcohol) matrix. Homogeneous and regular arrangement of the microgel particles was suggested by Bragg diffraction for the films prepared by varying the PVA/microgel ratio (from 6/4 to 3/7 (w/w)). It was proved that the regular arrangement and connection of the microgels by seeded polymerization in poly(vinyl alcohol) were possible. © 1996 John Wiley & Sons, Inc. 相似文献
45.
46.
Hiroshi Fukutomi Takeshi Yamamoto Kazushi Nonomura Kazuyoshi Takada 《Interface Science》1999,7(2):141-146
In order to understand the factors dominating grain boundary sliding, stress change tests and stress reversal tests were conducted on aluminum bicrystal specimens with high angle grain boundaries. It is found that small change in stress results in the remarkable change in the rate of grain boundary sliding. Stress reversal tests showed that grain boundary slide hardening does not work for the sliding to the direction opposite to that before the stress reversal. Mean internal stresses for the dislocations contributing to grain boundary sliding are experimentally measured by a method consisting of stress change and annealing. It is found that the velocity of dislocations in the grain boundary is in proportion to the mean effective stress. 相似文献
47.
Koji Ishizu Takashi Fukutomi 《Journal of polymer science. Part A, Polymer chemistry》1989,27(4):1259-1266
Anionic polymerization of methyl methacrylate (MMA) was carried out in tetrahydrofuran (THF) or THF/toluene mixture at ?78°C initiated by triphenylmethyl sodium or lithium as initiators. Highly syndiotactic PMMA of low polydispersity (M w/m n = 1.11–1.17) could be prepared with triphenylmethyl lithium in THF or THF/toluene mixture at ? 78°C. Moreover, PMMA macromonomer having one vinylbenzyl group per polymer chain was prepared by the couplings of living PMMA initiated by triphenylmethyl lithium with p-chloromethyl styrene (CMS) at ?78°C. The coupling reaction of living PMMA initiated by triphenylmethyl sodium with CMS was scarcely occurred. 相似文献
48.
Koji Ishizu Kazuhide Ino Takashi Fukutomi Toshio Kakurai 《Journal of polymer science. Part A, Polymer chemistry》1982,20(9):2555-2564
Lithium-metallated styrene–p-benzylstyrene copolymer was reacted with the branched polymer with chlorine groups at the pendant chain ends (multifunctional branched polymer) in tetrahydrofuran (THF) at 25°C. The rate constant was estimated from the changes in the concentration of metallated polymer by using photometrical measurements. The various reaction conditions were chosen and it became clear that the rate constants of intermolecular (k20) and intramolecular (k3intra) crosslinkings were derived separately at the second stage. k20 showed a constant value in spite of the molecular weight of crosslinker chains and was about equal to the rate constant of the grafting. The rate of intramolecular crosslinking at the second stage increased with decreasing the molecular weight of pendant chains of multifunctional branched polymer. 相似文献
49.
Kanamori K Nishida K Miyata N Shimoyama T Hata K Mihara C Okamoto K Abe Y Hayakawa S Matsugo S 《Inorganic chemistry》2004,43(22):7127-7140
A mononuclear peroxovanadium(V) complex with histamine-N,N-diacetate (histada), K[VO(O(2))(histada)], and a dinuclear peroxovanadium(V) complex with 2-oxo-1,3-diaminopropane-N,N,N',N'-tetraacetate (dpot), Cs(3)[(VO)(2)(O(2))(2)(dpot)], were prepared and characterized. The self-decomposition reaction was examined for these peroxovanadium(V) complexes as well as for K[VO(O(2))(cmhist)] (cmhist = N-carboxymethylhistidinate). The reaction profiles depicted by the absorbance change in the UV-vis spectrum show a sigmoid shape with an induction period. The induction period is reduced by the addition of acid, fluoride, thiocyanate, VO(2+), VO(2)(+), and trolox compared to the solution containing perchlorate. On the other hand, the induction period was elongated by the addition of chloride, bromide, and 2-tert-butyl-p-cresol. These behaviors are discussed on the basis of a radical chain mechanism. The self-decomposition reactions have also been followed by the (1)H and (51)V NMR and EPR spectra. These spectral studies as well as the UV-vis spectral study indicate that vanadium(V) is partly reduced to vanadium(IV) in the self-decomposition process. The histada complex yields a mixed-valence dinuclear complex in a concentrated solution, and the dpot complex yields a mixed-valence tetranuclear complex. The reduction of vanadium ion suggests that the peroxo ligand may act as a reducing agent. In order to know the fate of the peroxo ligand, we tried to detect superoxide anion and hydroxyl radical, which were anticipated to be produced in the self-decomposition process. The formation of superoxide anion was spectrophotometrically confirmed using two independent methods, including the reduction of cytochrome c and the reduction of sodium 4-[3-(iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate (WST-1). The formation of hydroxyl radical was confirmed by an EPR spin trapping technique. The oxidizing abilities of the peroxovanadium(V) complexes toward bovine serum albumin (BSA) were also evaluated. In the protein carbonyl assay, it was found that the total amount of protein carbonyl in BSA was increased by the reaction with the peroxovanadium complexes in the concentration-dependent manner. In addition, the oxidation of sulfhydryl group in BSA induced by the peroxovanadium complexes was confirmed. 相似文献
50.
Fostriecin, a potent protein phosphatase inhibitor and antitumor agent, has been enantioselectively synthesized in naturally occurring form via a versatile route, which also allows one to secure all possible stereoisomeres of the C1-C13 fragment including the C11 stereocenter and the geometry of the delta 12-double bond. 相似文献