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181.
182.
Shuichi Takahashi Mika Hayashida Tomonari Ogata Takamasa Nonaka Seiji Kurihara 《先进技术聚合物》2008,19(7):846-851
A photoactive over coating layer (OCL) material was prepared by mixing methacrylate copolymer resin, epoxy, and photoactive compounds, separately. The OCL material was found to show long shelf life at room temperature. However, serious lowering of the transparency of the OCL material was caused by post‐baking after alkali development. Microscopic and near infrared spectroscopic studies revealed that the phase separation between the hydrophilic copolymer resin and hydrophobic epoxy compound brought about the formation of wrinkly surface during the post‐baking after the alkali development, and consequently the transparency was lowered by light scattering due to the wrinkly surface. The carboxylic acid derivatives with long alkyl groups were effective for improvement of the transparency without shortening of the shelf life. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
183.
Takamasa Kitamoto 《Journal of fluorine chemistry》2008,129(4):286-293
In spite of quite small steric perturbation, substitution of proline (Pro) in the target pentapeptide proctolin (Arg-Tyr-Leu-Pro-Thr) for (4R)- as well as (4S)-4-fluoroproline led to apparent alteration of the pyrrolidine ring structure which eventually resulted in the significant conformational change of the whole molecules which was assumed on the basis of their NOESY spectra. 相似文献
184.
Tomohiro Hirano Ryosuke Yamaoka Takamasa Miyazaki Koichi Ute 《Journal of polymer science. Part A, Polymer chemistry》2010,48(24):5718-5726
Radical polymerization of N‐tert‐butoxycarbonylacrylamide (NBocAAm) in toluene at low temperatures in the presence of the fluorinated alcohols, 2,2,2‐trifluoroethanol, 1,1,1,3,3,3‐hexafluoro‐2‐propanol, and nonafluoro‐tert‐butanol, afforded atactic, heterotactic, and syndiotactic polymers, respectively. NMR analysis revealed that the fluorinated alcohols formed hydrogen bonding‐assisted complexes with NBocAAm, with different structures. The difference in the structures of the complexes was responsible for the differences in the induced stereospecificities. Based on the structures of the complexes between NBocAAm and the fluorinated alcohols, mechanisms for the three kinds of stereospecific radical polymerizations are proposed. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
185.
Tokunaga T Namiki S Yamada K Imaishi T Nonaka H Hirose K Sando S 《Journal of the American Chemical Society》2012,134(23):9561-9564
A fluorescent aptamer sensor was applied to the analysis of extracellular chemical transmitter dynamics. We utilized a tocopherol-labeled aptamer, which allowed the direct anchoring of the fluorescent aptamer on the cell surface while retaining its performance as a fluorescent sensor. The fast-responsive fluorescent DNA aptamer sensor, which targets adenine compounds, was anchored on the surface of brain astrocytes. Fluorescence imaging of the aptamer-anchored astrocytes enabled the real-time monitoring of release of adenine compounds as a gliotransmitter, which was synchronized with calcium wave propagation in neighboring cells. 相似文献
186.
Takamasa Suzuki 《Journal of organometallic chemistry》2010,695(1):128-7854
The catalytic enantioselective allylation of aldehydes with β-carbonyl allyltributylstannanes in the presence of chiral indium complexes gave the optically active homoallylic alcohols, which can be converted to the corresponding optically active α-methylene-γ-butyrolactones. 相似文献
187.
Ikeda T Sakota K Kawashima Y Shimazaki Y Sekiya H 《The journal of physical chemistry. A》2012,116(15):3816-3823
Photoionization-induced water migration in the trans-formanilide-water 1:1 cluster, FA-(H(2)O)(1), has been investigated by using IR-dip spectroscopy, quantum chemical calculations, and ab initio molecular dynamics simulations. In the S(0) state, FA-(H(2)O)(1) has two structural isomers, FA(NH)-(H(2)O)(1) and FA(CO)-(H(2)O)(1), where a water molecule is hydrogen-bonded (H-bonded) to the NH group and the CO group, respectively. In addition, the S(1)-S(0) origin transition of FA(CO)-(H(2)O)(2), where a water dimer is H-bonded to the CO group, was observed only in the [FA-(H(2)O)(1)](+) mass channel, indicating that one of the water molecules evaporates completely in the D(0) state. These results are consistent with a previous report [Robertson, E. G. Chem. Phys. Lett., 2000, 325, 299]. In the D(0) state, however, [FA-(H(2)O)(1)](+) produced by photoionization via the S(1)-S(0) origin transitions of FA(NH)-(H(2)O)(1) and FA(CO)-(H(2)O)(1) shows essentially the same IR spectra. Compared with the theoretical calculations, [FA-(H(2)O)(1)](+) can be assigned to [FA(NH)-(H(2)O)(1)](+). This means that the water molecule in [FA-(H(2)O)(1)](+) migrates from the CO group to the NH group when [FA-(H(2)O)(1)](+) is produced by photoionization of FA(CO)-(H(2)O)(1). [FA-(H(2)O)(1)](+) produced by photoionization of FA(CO)-(H(2)O)(2) also shows the IR spectrum corresponding to [FA(NH)-(H(2)O)(1)](+). In this case, the water migration from the CO group to the NH group occurs with the evaporation of a water molecule. Ab initio molecular dynamics simulations revealed the water migration pathway in [FA-(H(2)O)(1)](+). The calculations of classical electrostatic interactions show that charge-dipole interaction between FA(+) and H(2)O induces an initial structural change in [FA-(H(2)O)(1)](+). An exchange repulsion between the lone pairs of the CO group and H(2)O in [FA-(H(2)O)(1)](+) also affects the initial direction of the water migration. These two factors play important roles in determining the initial water migration pathway. 相似文献
188.
Li D Ikeda T Matsuoka N Nohara T Zhang H Sakamoto T Nonaka G 《Chemical & pharmaceutical bulletin》2006,54(10):1425-1428
From the unripe fruits of Lo Han Kuo (Siraitia grosvenori), a Chinese medicinal plant, two new cucurbitane triterpene glycosides, 20-hydroxy-11-oxomogroside IA(1) (1) and 11-oxomogroside IIE (2), were isolated along with five known cucurbitane glycosides, 11-oxomogroside IA(1) (3), mogroside IIE (4), mogroside III (5), mogroside IVA (6), and mogroside V (7), and two flavonoid glycosides, kaempferol 7-O-alpha-L-rhamnopyranoside (8) and kaempferol 3,7-di-O-alpha-L-rhamnopyranoside (9). Their structures were determined on the basis of detailed analyses of 1D, 2D-NMR spectroscopic methods and by comparing with literature values. This paper describes the first investigation of unripe bitter Lo Han Kuo fruits. 相似文献
189.
Yasuo Ohta Matsumi Doe Yoshiki Morimoto Takamasa Kinoshita 《Journal of heterocyclic chemistry》2000,37(4):731-734
The naturally‐occurring furanonaphthoquinones 1a‐d have been synthesized from 3‐furancarboxylic acid and 2,3‐dimethoxybenzaldehyde via the Birch reduction‐elimination. 相似文献
190.
Seiji Kurihara Teppei Yoshioka Tomonari Ogata Alam Md Zahangir Takamasa Nonaka 《Liquid crystals》2013,40(10):1219-1223
We have synthesized azobenzene-based molecules containing either one or two chiral groups. A cholesteric phase can be induced by adding the chiral azobenzene compounds to a host nematic liquid crystal. We investigated the effects of the trans-cis photoisomerization of the chiral azobenzene compounds on the properties of the cholesteric phase, such as the helical pitch length. This can be increased or decreased by the photoisomerization of the chiral azobenzene compounds. We discuss the photochemically driven change in the helical pitch of the cholesteric phase with respect to structural effects involving the chiral groups. 相似文献