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51.
Kida T Minabe T Nakano S Akashi M 《Langmuir : the ACS journal of surfaces and colloids》2008,24(17):9227-9229
Novel types of layer-by-layer (LbL) assembly films were successfully fabricated onto a solid substrate through the inclusion complex formation between partially 2,3- O-methylated amyloses (MAs) and polytetrahydrofuran (PTHF). The formation of the LbL assembly films was confirmed by quartz crystal microbalance (QCM) analysis, atomic force microscopy (AFM) observation, and X-ray diffraction (XRD) measurement. The film formation was significantly affected by the methylation degree of amylose. When MAs with 8 and 20% methylation were used as hosts, the formation of LbL assembly films with PTHF was clearly observed. On the other hand, MAs with more than 33% methylation barely formed LbL assembly films with PTHF. 相似文献
52.
Suguru Ito 《Tetrahedron》2008,64(42):9879-9884
The asymmetric total syntheses of (+)-curcutetraol and (+)-sydonol, phenolic bisabolane-type sesquiterpenoids having chiral tertiary alcohol moiety in the o-position of a phenol, were achieved in high enantiomeric excesses (99% ee). The chiral tertiary benzylic alcohol moiety of these compounds was constructed by an asymmetric synthesis using an easily available chiral aminal, (−)-(2R,5S)-2-methoxycarbonyl-3-phenyl-1,3-diazabicyclo[3.3.0]octane. The absolute configurations of both (+)-curcutetraol and (+)-sydonol have been assumed to be S-configuration based on the stereochemical course of the well established asymmetric synthesis used in the syntheses. 相似文献
53.
Mesoporous aluminosilicate (Al-MCM-41) was found to be an effective and reusable catalyst for 1,3-addition of silyl enol ethers to nitrones. The reaction proceeded under mild reaction conditions to afford the corresponding β-(siloxyamino)ketones in high yields. Furthermore, a unique chemoselectivity of a nitrone over an aldehyde and an acetal, which are more reactive toward silyl enol ether in the presence of Al-MCM-41 than a nitrone, was observed. 相似文献
54.
Kaoru Taketani Kenji Mishima Takashi Ino Tamaki Yoshioka Suguru Muto Takahiro Morishima Hirohiko M. Shimizu Takayuki Oku Junichi Suzuki Takenao Shinohara Kenji Sakai Hiromi Sato Katsuya Hirota Yoshie Otake Masaaki Kitaguchi Masahiro Hino Yoshichika Seki Yoshihisa Iwashita Masako Yamada Masahiro Ichikawa Takanori Sugimoto Shinsuke Kawasaki Sachio Komamiya Yoshio Kamiya Hidetoshi Otono Satoru Yamashita Peter Geltenbort 《Physica B: Condensed Matter》2009,404(17):2643-2645
We obtained highly polarized very cold neutrons through a quadrupole magnet with a large aperture. When neutrons go through a quadrupole magnet, parallel-spin neutrons are attracted to the magnet axis and anti-parallel-spin neutrons are repelled off the axis. Therefore, the neutrons through a sufficiently long quadrupole magnet have completely parallel-spin. At the downstream of the quadrupole magnet, we placed another quadrupole magnet to divide neutrons into two regions depending on their spin directions. We obtained the neutron polarization from the integrated count of the two regions and found it was 99.88±0.09 (stat.)±0.05 (syst.)%. 相似文献
55.
56.
Controlled construction of four out of five diastereomers of macrocyclic boronic ester was achieved in high yield by utilizing the self-assembly of two chiral components with the proper choice of reaction conditions. Three diastereomers could be constructed as enantiopure forms by properly changing the chirality combination between the two building blocks. Furthermore, the methodology could be applicable to the three-component self-assembly of enantiopure macrocyclic boronic esters having two different diboronic acid moieties. 相似文献
57.
J Odo S Torimoto S Nakanishi T Niitani H Aoki M Inoguchi Y Yamasaki 《Chemical & pharmaceutical bulletin》2012,60(7):846-853
The photodegradation of environmental mutagens, such as 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), 2-amino-3-methyl-9H-pyrido[2,3-b]indole (MeAαC), and 2-amino-3-methyl-imidazo[4,5-f]quinoline (IQ), was investigated by visible irradiation in the presence of xanthene dyes as photosensitizers. Although the environmental mutagens themselves were very stable during visible irradiation under the conditions in this study, they were effectively photodegraded in the presence of the xanthene dyes (erythrosine, rose bengal, and phloxine). Moreover, photodegradation of the mutagens was further enhanced for xanthene dyes loaded onto a water-soluble diethylaminoethyl (DEAE)-dextran anion-exchanger via ionic interactions (xanthene-dyeDEX). Photodegradation was inhibited by O2 removal from the reaction solution. In ESR spin-trapping experiments using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a trapping reagent, signals characteristic of DMPO-?OH (hydroxyl radical) were observed in the presence of xanthene-dyeDEX. These results suggest that reactive oxygen species derived from O2, such as singlet molecular oxygen (?1O2) and/or ?OH, were active participants in photodegradation of the mutagens in the presence of xanthene dyes or xanthene-dyeDEX. 相似文献
58.
Kohji Yoshinaga Suguru Motokucho Ken Kojio Akemi Nakai 《Colloid and polymer science》2012,290(12):1221-1226
Dispersion of fullerene, C60, by addition of polymethacrylate dispersant in methyl methacrylate (MMA) and incorporation of C60 into poly(methyl methacrylate) (PMMA) were investigated. Copolymers synthesized by radical copolymerization of MMA and 2-naphthyl methacrylate (NMA), poly(MMA-co-NMA), effectively dispersed C60 in MMA to form clusters of 20?nm. In these cases, addition of minimal 110 naphthyl groups per unit C60 molecule afforded to give clusters with minimum of 20?nm sizes. Furthermore, block copolymers, poly(MMA-b-NMA) with MMA/NMA mole ratio from 12:1 to 20:1, also efficiently dispersed C60 to give formation of clusters of 20?nm size by addition of minimal 40 naphthyl groups per unit C60 molecule, which was corresponding to approximate nine layers of naphthyl group in block copolymer adsorbed on the surface of the cluster. Hybrid films of C60/PMMA, prepared by casting of C60-dispersed solution containing PMMA, exhibited absorbance at 400?nm linearly increased with C60 content. 相似文献
59.
Nakayama R Matsubara H Fujino D Kobatake T Yoshida S Yorimitsu H Oshima K 《Organic letters》2010,12(24):5748-5751
Tin hydride mediated radical addition of organic halide to 2-(2,2,2-trifluoroethylidene)-1,3-dithiane 1-oxide has been devised. The reaction is equivalent to an unrealizable radical addition to trifluoromethylketene, providing useful α-trifluoromethyl carbonyl equivalents. The trifluoromethyl and the sulfoxide groups of the substrate play key roles for the success of the radical addition, lowering the barrier of the radical addition step and controlling the stereoselectivity of the reaction, which DFT calculations have elucidated. 相似文献
60.
Kenichiro Takakura Suguru Funasaki Isao Tsunoda Hidenori Ohyama Daisuke Takeuchi Toshiyuki Nakashima Mutsuo Shibuya Katsuya Murakami Eddy Simoen Cor Claeys 《Physica B: Condensed Matter》2012,407(15):2900-2902
A transparent electrode of Si doped β-Ga2O3 films for solar cells, flat panel displays and other devices, which consists of chemically abundant and ecological friendly elements of gallium and oxygen, was grown on silicon substrates by RF magnetron sputtering using sintered Ga2O3 and Si target. The Si composition in the β-Ga2O3 film is determined by electron dispersive X-ray spectroscopy. The X-ray photoelectron spectroscopy peak ratio of oxygen over gallium decreases with increasing Si content. It is concluded that Si substitutes for the Ga sites in the β-Ga2O3 film. 相似文献