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排序方式: 共有181条查询结果,搜索用时 46 毫秒
131.
Eriko Watanabe Sai‐Cheong Chung Shin‐ichi Nishimura Yuki Yamada Masashi Okubo Keitaro Sodeyama Yoshitaka Tateyama Atsuo Yamada 《Chemical record (New York, N.Y.)》2019,19(4):792-798
Owing to developments in theoretical chemistry and computer power, the combination of calculations and experiments is now standard practice in understanding and developing new materials for battery systems. Here, we briefly review our recent combined studies based on density functional theory and molecular dynamics calculations for electrode and electrolyte materials for sodium‐ion batteries. These findings represent case studies of successful combinations of experimental and theoretical methods. 相似文献
132.
Inside Back Cover: Giant Amplification of Photoswitching by a Few Photons in Fluorescent Photochromic Organic Nanoparticles (Angew. Chem. Int. Ed. 11/2016) 下载免费PDF全文
133.
Keitaro Ishii Terry A. Lyle W. Bernd Schweizer Bruno Frei 《Helvetica chimica acta》1982,65(2):595-599
On 1n,π*-excitation, the title compound 2 undergoes a photoinduced intramolecular [4 + 2]-cycloaddition affording the tetracyclic enol ether 3 as the only product in 79% yield. The assigned structure of 3 was confirmed by its conversion to the p-nitrobenzoate 6 whose structure was determined by X-ray analysis. 相似文献
134.
Keitaro Kiyosawa 《Journal of solution chemistry》2005,34(1):1-7
The freezing points of mixtures of benzene, C6H6, with one of its isotopes, C6D6 and 13C6H6, and those of acetic acid CH3COOH with its isotopes, CH3COOD and CD3COOD, were measured as functions of the molal concentrations of C6D6 and 13C6H6, CH3COOD and CD3COOD, respectively. They changed linearly or non-linearly with increasing molal concentration of C6D6 and 13C6H6, CH3COOD, and CD3COOD, respectively. These findings confirm Kiyosawas previous conclusion drawn from experiments on the freezing points of mixtures of H216O with H218O or H217O. This hypothesis states that even a difference in the number of neutrons in the hydrogen or oxygen atoms of water molecules makes water molecules behave as different entities with respect to the colligative properties of solutions. This concept can be extended to mixtures of ordinary benzene with either of its isotopes, C6D6 or 13C6H6, and those of ordinary acetic acid CH3COOH with either of its isotopes, CH3COOD or CD3COOD. 相似文献
135.
Keitaro Senga Kiyoko Fukami Hashime Kanazawa Sadao Nishigaki 《Journal of heterocyclic chemistry》1982,19(4):805-808
New synthetic routes to pyrido[3,2-d]pyrimidines starting with 5-amino-1,3,6-trimethyluracil (I) or 1,3,6-trimethyl-5-nitrouracil (X) are described. Thus, condensation of I with arylaldehydes gave 5-arylideneamino-1,3,6-trimethyluracils (IIa-h), which upon heating with dimethylformamide dimethylacetal afforded 6-aryl-1,3-dimethylpyrido[3,2-d]pyrimidine-2,4(1H,3H)-diones (Va-h) via 5-arylideneamino-1,3-dimethyl-6-(2-dimethylaminovinyl)uracils (IIIa-h). On the other hand, reaction of X with phenylacetaldehyde in the presence of base yielded Va and its 5-oxide (XI). 相似文献
136.
Hideo Nagashima Keitaro Yamaguchi Katsunori Mukai Kenji Itoh 《Journal of organometallic chemistry》1985,291(2):c20-c22
Divalent ruthenium complexes, (η5-C5R5)RuL2X (R = H, CH3; X = Br, Cl), are formed by thermal decomposition of (η5-C5R5)Ru(CH3)X(η3-C3H5) in the presence of several neutral ligands. 相似文献
137.
Sadao Nishigaki Noriko Mizushima Hashime Kanazawa Misuzu Ichiba Keitaro Senga 《Journal of heterocyclic chemistry》1985,22(4):1029-1032
Synthesis and in vitro antibacterial activity of 7-(1′-alkylhydrazino)-1,8-naphthyridines related to nalidixic acid were investigated. Namely, treatment of 7-alkylamino-1-ethyl-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylic acids 1a-d with sodium nitrite in the presence of hydrochloric acid gave the 1-ethyl-1,4-dihydro-7-(N-nitrosoalkylamino)-4-oxo-1,8-naphthyridine-3-carboxylic acids 2a-d , which upon reacting with zinc dust in acetic acid gave the 7-(1′-alkylhydrazino)-1-ethyl-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylicacids 3a-d. The compound 3a was alternately obtained by the reaction of 7-chloro-1-ethyl-1,4-dihydro-4-oxo-1,8-naphth-yridine-3-carboxylic acid ( 4 ) with methylhydrazine. The reaction of 7-chloro-4-hydroxy-1,8-naphthyridine-3-carboxylic acid ( 5 ) with methylhydrazine gave the 4-hydroxy-7-(1′-methylhydrazino)-4-oxo-1,8-naphthyridine-3-carboxylic acid ( 6 ), which upon treatment with alkyl halides afforded the 1-alkyl-1,4-dihydro-7-(1′-methyl-hydrazino)-4-oxo-1,8-naphthyridines 3a and 3e-g. The reaction of the appropriate 3 with ketones gave the corresponding 7-(1′-methylalkylidenehydrazino)-1,8-naphthyridines 7a-c and 8a-b. Among the compounds prepared, certain 3 and 7 exhibited good activity against Gram-negative bacteria. 相似文献
138.
Keitaro Senga Joze Kobe Roland K. Robins Darrell E. O'Brien 《Journal of heterocyclic chemistry》1975,12(5):893-898
The synthesis of a new series of alkylxanthine analogs containing a bridgehead nitrogen atom is reported. 1,3-Dialkylpyrazolo[1,5-a]-1,3,5-triazine-2,4-diones, were prepared by the treatment of 3-methylpyrazolo[1,5-a]-1,3,5-triazine-2,4-dione (3) with the corresponding alkyl iodide. Similarly, the reaction of 3-methyl-7-phenylpyrazolo[1,5-a]-1,3,5-dialkyl-7-phenylpyrazolo[1,5-a]-1,3,5-triazine-2,4-diones. The starting materials, 3 and 17 , were prepared via the reaction of an appropriate 3-aminopyrazole with ethoxycarbonyl isothiocyanate. Several 8-bromo derivatives were prepared by direct bromination of the 1,3-dialkylpyrazolo[1,5-a]-1,3,5-triazine-2,4-diones. 相似文献
139.
Keiji Kamogawa Akira Namiki † Nobuaki Nakashima Keitaro Yoshihara ‡ Isamu Ikegami§ 《Photochemistry and photobiology》1981,34(4):511-516
Abstract— Both [15-13 C] and [14-13 C] all-trans-retinals were synthesized. Bacteriorhodopsin containing [14-13 C]retinal as a chromophore, when solubilized with octyl-β-D-glucoside, showed characteristic resonances at 125 and 118 ppm from tetramethyl silane. The former was assigned to the signal from free retinal and the latter from protonated Sehiff base. When the bacteriorhodopsin was denatured in sodium dodecyl sulfate, the signal at 118 ppm disappeared, while the signal at 125 ppm rather increased.
In the case of bacteriorhodopsin containing [15-13 C]retinal, when solubilized with Triton X-100, a characteristic resonance at 169 ppm was distinguishable as a shoulder peak superimposed on the broad signal of carbonyl carbons and it was assigned to the signal from the protonated Sehiff base. The other signal observed at 191 ppm was from free retinal.
These results suggested that the Sehiff base of bacteriorhodopsin is protonated in the dark. 相似文献
In the case of bacteriorhodopsin containing [15-
These results suggested that the Sehiff base of bacteriorhodopsin is protonated in the dark. 相似文献
140.
Yoshimoto K Nishizawa S Minagawa M Teramae N 《Journal of the American Chemical Society》2003,125(30):8982-8983
Nucleobase recognition in water is successfully achieved by the use of an abasic site (AP site) as the molecular recognition field. We intentionally construct the AP site in DNA duplex so as to orient the AP site toward a target nucleobase and examine the complexation of 2-amino-7-methylnaphthyridine (AMND) with nucleobases at the AP site. AMND is found to selectively bind to cytosine (C) base with a 1:1 binding constant of >106 M-1, accompanied by remarkable quenching of its fluorescence. In addition to hydrogen bonding, a stacking interaction with nucleobases flanking the AP site seems responsible for the binding properties of AMND at the AP site. Possible use of AMND is also presented for selective and visible detection of a single-base alternation related to the cytosine base. 相似文献