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101.
Toshiyuki Nagoshi Nobuyuki Watanabe Sohkichi Suzuki Masashi Usa Haruo Watanabe Tsutomu Ichimura Humio Inaba 《Photochemistry and photobiology》1992,56(1):89-94
Abstract— Spectral analyses of low level chemiluminescence were carried out by using a newly developed polychromatic spectrometer in which a diffracted photon emission was detected simultaneously using a two dimensional photon-counting device. The spectrometer was sensitive in the 400–800 nm wavelength range. Low level chemiluminescence generated in a 1 nM luminol solution could be detected as a spectrum, showing a peak at 430 nm. Short lifetime photon emission from singlet oxygen showed only two peaks at around 630 and 700 nm in this highly time-resolved spectroscopy. Lipid peroxidation of linoleic acid by the lipoxygenase emitted a low intensity peak centered at 440 nm, but singlet oxygen emission arising from the decomposition of lipid peroxide was not observed. An injured cotyledon of a soybean seedling gave a broad emission centered at 725 nm in the absence of hydrogen peroxide, while in its presence a different emission peak appeared at a shorter wavelength (515 nm). Oxygenated, fluorescent components in the soybean seedling may be the emitting species. Singlet oxygen and triplet carbonyl groups were shown to be unlikely sources of the emission. 相似文献
102.
103.
K Yokogawa E Nakashima F Ichimura T Yamana 《Chemical & pharmaceutical bulletin》1985,33(10):4581-4586
104.
105.
Yamada T Shinoda S Kikawa K Ichimura A Teraoka J Takui T Tsukube H 《Inorganic chemistry》2000,39(14):3049-3056
A variety of lariat ethers were employed to solubilize water-soluble cytochrome c in methanol, in which alcohol, ether, ester, amine, and amide functionalities were attached as cation-ligating side arms to 18-crown-6, 15-crown-5, and 12-crown-4 rings. Among these lariat ethers, the alcohol-armed 18-crown-6 derivative offered the highest solubilization efficiency for cytochrome c via supramolecular complexation. The resulting cytochrome c-lariat ether complexes were electrochemically and spectroscopically characterized and confirmed to have redox-active heme structures of 6-coordinate low-spin population in methanol. Some of them catalyzed the oxidation of pinacyanol chloride with hydrogen peroxide in methanol and exhibited higher activities than unmodified cytochrome c and its poly(ethylene glycolated) derivative. Since the supramolecular complexation between lariat ether and cytochrome c includes extremely simple procedures, it provides a facile preparation method of effective biocatalysts working in organic solvents from metalloproteins. 相似文献
106.
Nagano M Suzuki T Ichimura T Okutsu T Hiratsuka H Kawauchi S 《The journal of physical chemistry. A》2005,109(26):5825-5831
Production and photoexcited dynamics of reaction intermediates with photolyses of benzyl chloride (BzCl) and methyl-substituted benzyl chlorides (MeBzCls) were studied by using stepwise two-color laser excitation transient absorption (TC-TA) and two-color laser excitation time-resolved thermal lensing (TC-TRTL) measurements. With photoexcitation of BzCl the formation of transient photorearranged isomer was suggested in the previous paper [Res. Chem. Intermed. 2001, 27, 137]. Such an isomer formation for MeBzCls was also observed in a 248 nm excitation. It was found that further photoexcitation of the isomers with the 308 nm light caused photodissociation to yield the corresponding benzyl radicals. The reaction quantum yield and the molar absorptivity of the photorearranged isomer of BzCl were estimated. The heat of reaction for the photodissociation of the isomer was successfully determined with the TC-TRTL measurement. These experimental results were consistent with MO calculations. 相似文献
107.
Syuji Fujioka Tadao Ichimura Yasuo Shinohara Koichiro Hayashi 《Journal of polymer science. Part A, Polymer chemistry》1968,6(5):1109-1120
The rate of radiation-induced polymerization of isoprene in aqueous solution of silver nitrate is 20–50 times as fast as the rate of radiation-induced polymerization of pure isoprene. The formation of a 1:2 complex of isoprene and silver nitrate was confirmed spectrometrically, and this complex seems to polymerize by attack of an active species. The equilibrium constant Kf and the extinction coefficient E of the complex were estimated to be 0.18 and 1.4, respectively. The polymerization mechanism was concluded to be a radical one, based on the effects of inhibitors. The polyisoprene obtained had a crosslinked structure, was insoluble, and did not give a distinct melting point. The 1,2 structure was the predominant polyisoprene configuration. This was interpreted on the basis of the frontier electron density of isoprene. 相似文献
108.
Kunihiro Ichimura Shoji Watanabe 《Journal of polymer science. Part A, Polymer chemistry》1980,18(3):891-902
Reaction of the homopolymer of 2-chloroethyl vinyl ether and the copolymer of N-vinylpyrrolidone with stilbazole produced photosensitive polymers. The photocrosslinking mechanism is discussed. Irradiation of a film of the water-soluble photosensitive polymer yielded insolubilized material in which the enzymes were entrapped. The activity of entrapped invertase, glucoamylase, and catalase was 30, 60, and 35%, respectively. 相似文献
109.
T. Ichimura A. Kawana T. Suzuki T. Ebata N. Mikami 《Journal of photochemistry and photobiology. A, Chemistry》1994,80(1-3):145-150
Laser-induced fluorescence spectra of jet-cooled chlorotoluene molecules are reported for the S1 state. The fluorescence excitation spectrum of m-chlorotoluene shows some low-frequency bands up to 200 cm−1 above the S1 origin, which are assigned to internal rotational modes of the methyl group. Beyond 300 cm−1 and up to approximately 1500 cm−1 sharp vibrational bands are observed, which are assigned by measurement of the dispersed fluorescence spectrum on excitation of each vibrational band. The vibrational energies of the C---Cl stretching modes for the o-, m- and p-chlorotoluene molecules are 341, 378 and 360 cm−1 respectively in the S1 state. 相似文献
110.
F Tani M Matsu-ura S Nakayama M Ichimura N Nakamura Y Naruta 《Journal of the American Chemical Society》2001,123(6):1133-1142
Two kinds of novel cytochrome P450 models, which have alkanethiolate axial ligands and hydroxyl groups inside molecular cavities, were designed and synthesized as functional O(2) binding systems. A superstructured porphyrin, designated as "twin-coronet" porphyrin, was used as the common framework of the model complexes. This porphyrin bears four binaphthalene bridges on the both sides and forms two pockets surrounded by the bulky aromatic rings. Thiobenzyloxy and thioglycolate moieties, which contain an alkanethiolate group exhibiting various electron-donating abilities and degrees of bulkiness, were covalently linked to twin-coronet porphyrin to yield thiolate-coordinated hemes, TCP-TB and TCP-TG (twin-coronet porphyrin with thiobenzyloxy and thioglycolate groups), respectively. Both ferric complexes exhibited high stability during usual experimental manipulation under air and were characterized by MS, UV/vis, ESR spectroscopies, and CV. The ESR spectra exhibited low-spin signals (TCP-TB: g = 2.334, 2.210, 1.959; TCP-TG: g = 2.313, 2.209, 1.966). The cyclic voltammogram of TCP-TB in CH(3)CN gave a quasi-reversible wave which corresponds to the Fe(III)/Fe(II) redox couple: E(p)()(/2) = -1.35 V (vs Fc/Fc(+)). On the other hand, TCP-TG showed a fine reversible wave: E(1/2) (Fe(III)/Fe(II)) = -1.12 V. The stable dioxygen adducts were formed in the reaction of the ferric complexes with KO(2) under an oxygen atmosphere and characterized by UV/vis and resonance Raman (RR) spectroscopies. In the RR spectra, the nu(O--O) bands of the dioxygen adducts were observed at 1138 cm(-1) (TCP-TB) and 1137 cm(-1) (TCP-TG). The hypothesis that hydrogen bonding between the bound oxygen and the hydroxyl groups of the binaphthyl moieties could increase their stability was verified by RR spectroscopy. When all hydroxyl groups were deuterated, only the frequencies of the nu(O--O) bands were upshifted by 2 cm(-1) without any perturbation in the porphyrin skeleton. This work shows the first direct evidence for a hydrogen bond to dioxygen in an oxy form of a thiolate-coordinated heme model system. These results are discussed in context of the process of dioxygen binding and activation in cytochrome P450. 相似文献