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31.
Ui M Tanaka Y Araki Y Wada T Takei T Tsumoto K Endo S Kinbara K 《Chemical communications (Cambridge, England)》2012,48(39):4737-4739
A chimeric protein (N-PYP-Hla), consisting of staphylococcal pore-forming toxin α-hemolysin (Hla) and photoactive yellow protein (PYP), exhibited photoresponsive hemolytic activities, where visible light irradiation gave rise to retardation of hemolysis at 25 °C. 相似文献
32.
A highly active catalyst for the skeletal isomerization of butane to isobutane was obtained by mechanically mixing SO4/ZrO2 and Ru/SnO2; Ru/SO2 was prepared by impregnating tin hydroxide with a solution of RuCl3 followed by calcining at 450°C (0.5 wt.% Ru). The catalyst was much more active than Ru-SO4/ZrO2 prepared by co-impregnation of zirconia with the Ru and sulfate materials the temperature difference to show the same conversion between both catalysts being 57°C. The effect of mixing of Ru was observed with other metal oxides as supports, Fe2O3, Al2O3, ZrO2, TiO2, and SiO2; the calcination temperature of the Ru-impregnated hydroxides was 250, 300, and 400°C for the latter three, respectively. 相似文献
33.
Hiroki Hirai Kiichi Nakajima Soichiro Nakatsuka Kazushi Shiren Jingping Ni Shintaro Nomura Toshiaki Ikuta Takuji Hatakeyama 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(46):13785-13789
The development of a one‐step borylation of 1,3‐diaryloxybenzenes, yielding novel boron‐containing polycyclic aromatic compounds, is reported. The resulting boron‐containing compounds possess high singlet‐triplet excitation energies as a result of localized frontier molecular orbitals induced by boron and oxygen. Using these compounds as a host material, we successfully prepared phosphorescent organic light‐emitting diodes exhibiting high efficiency and adequate lifetimes. Moreover, using the present one‐step borylation, we succeeded in the synthesis of an efficient, thermally activated delayed fluorescence emitter and boron‐fused benzo[6]helicene. 相似文献
34.
[reaction: see text] A convergent synthetic route to the CDEFG-ring system of gambieric acids, potent antifungal polycyclic ether marine natural products, has been developed. The present synthesis features convergent union of the CD- and G-rings through esterification, formation of the E-ring as a lactone form, stereoselective allylation to set the C26 stereocenter, and ring-closing metathesis reaction to construct the nine-membered F-ring. 相似文献
35.
Prof. Dr. Hayato Tsurugi Prof. Dr. Kazushi Mashima 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(4):913-919
Herein, we provide a new protocol to reduce various transition-metal complexes by using organosilicon compounds in a salt-free fashion with the great advantage of generating pure low-valent metal species and metallic(0) nanoparticles, in sharp contrast to reductant-derived salt contaminants obtained by reduction with metal reductants. The organosilicon derivatives 1,4-bis(trimethylsilyl)-2,5-cyclohexadiene ( 1 a ), 1-methyl-3,6-bis(trimethylsilyl)-1,4-cyclohexadiene ( 1 b ), 1,4-bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadiene ( 2 a ), 2,5-dimethyl-1,4-bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadiene ( 2 b ), 2,3,5,6-tetramethyl-1,4-bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadiene ( 2 c ), and 1,1′-bis(trimethylsilyl)-1H,1′H-4,4′-bipyridinylidene ( 3 ) all served as versatile reductants for early transition-metal complexes and produced only easy-to-remove organic compounds, such as trimethylsilylated compounds and the corresponding aromatics, for example, benzene, toluene, pyrazine, and 4,4′-bipyridyl, as the byproducts. The high solubility of the reductants in organic solvents enabled us to monitor the catalytic reactions directly and to detect any catalytically active species so that we could elucidate the reaction mechanism. 相似文献
36.
Takehiro Yamagishi Atsushi Kinbara Noriko Okubo Shunpei Sato Haruhiko Fukaya 《Tetrahedron: Asymmetry》2012,23(24):1633-1639
The diastereoselective synthesis of Pro-Phe phosphinyl dipeptide isosteres in protected form was achieved by starting from optically active 1,1-diethoxyethyl(aminomethyl)phosphinate. Our methodology involves diastereoselective α-alkylation and β′-alkylation of phosphinate derivatives with an asymmetric center at the phosphorus atom. 相似文献
37.
Takashi Uneyama Yuichi Masubuchi Kazushi Horio Yumi Matsumiya Hiroshi Watanabe Jai A. Pathak C. Michael Roland 《Journal of Polymer Science.Polymer Physics》2009,47(11):1039-1057
For type‐A polymer chains having type‐A dipoles parallel along the chain backbone (such as cis‐polyisoprene), a theoretical analysis was conducted for the rheodielectric response to relate this response to the chain dynamics. The rheodielectric response in the shear gradient direction (y direction) under steady shear was analyzed on the basis of a Langevin equation. It turned out that the relaxation time is exactly the same for the rheodielectric relaxation function and the end‐to‐end vector autocorrelation function defined in the shear gradient direction and that the relaxation mode distribution also coincides for these functions at least up to second order of the shear rate (corresponding to the lowest order of nonlinearities of these functions). Consequently, the Green‐Kubo theorem holds satisfactorily, and the rheodielectric intensity is proportional to the squared chain size in y direction, 〈R〉, averaged over the time‐independent conformational distribution function under steady shear. The situation is more complicated under large amplitude oscillatory strain (LAOS) because the conformational distribution function fLAOS is synchronized with LAOS to oscillate at the LAOS frequency, Ω. The rheodielectric response under LAOS was found to detect this oscillation of fLAOS being coupled with the oscillation of the electric field, E(t) = E0sin ωt, and thus, split into a series of components oscillating at frequencies ω and ω ± βΩ (β = 1, 2, …). Consequently, the rheodielectric intensity under LAOS, evaluated from the component oscillating at ω, is no longer proportional to 〈R〉. However, the relative mode distribution and relaxation time of this component can be directly related to those of the end‐to‐end vector correlation averaged over a nonoscillatory part of fLAOS. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1039–1057, 2009 相似文献
38.
Cerium(IV) Hexanuclear Clusters from Cerium(III) Precursors: Molecular Models for Oxidative Growth of Ceria Nanoparticles 下载免费PDF全文
Dr. Laurent Mathey Mitali Paul Prof. Dr. Christophe Copéret Prof. Dr. Hayato Tsurugi Prof. Dr. Kazushi Mashima 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(38):13454-13461
Reactions of cerium(III) nitrate, Ce(NO3)3?6 H2O, with different carboxylic acids, such as pivalic acid, benzoic acid, and 4‐methoxybenzoic acid, in the presence of a tridentate N,N,N‐donor ligand, diethylenetriamine (L1), under aerobic conditions yielded the corresponding cerium hexamers Ce6O8(O2CtBu)8(L1)4 ( 1 ), Ce6O8(O2CC6H5)8(L1)4 ( 2 ), and Ce6O8(O2CC6H4‐4‐OCH3)8(L1)4 ( 3 ). Hexamers 1 , 2 , and 3 contain the same octahedral CeIV6O8 core, in which all interstitial oxygen atoms are connected by μ3‐oxo bridging ligands. In contrast, treatment of the CeIV precursor (NH4)2Ce(NO3)6 (CAN) with pivalic acid and the ligand L1 under the same conditions afforded Ce6O4(OH)4(O2CtBu)12(L1)2 ( 4 ), exhibiting a deformed octahedral CeIV6O4(OH)4 core containing μ3‐oxo and μ3‐hydroxo moieties in defined positions. In contrast to the formation of 1 – 3 , the use of N‐methyldiethanolamine (L) in the reaction with Ce(NO3)3?6 H2O and pivalic acid afforded a previously reported CeIII dinuclear cluster, Ce2(O2CtBu)6L2, even in the presence of dioxygen. ESI‐MS analysis of the reaction mixture clearly indicated the importance of the ligand L1 in promoting oxidation of the CeIII aggregates, [Cen(O2CtBu)3n(L1)2], which is necessary for the formation of CeIV hexamers. 相似文献
39.
Kazushi Ueda 《Communications in Mathematical Physics》2006,264(1):71-85
We prove the homological mirror conjecture for toric del Pezzo surfaces. In this case, the mirror object is a regular function
on an algebraic torus We show that the derived Fukaya category of this mirror coincides with the derived category of coherent sheaves on the original
manifold.
Supported by JSPS Fellowships for Young Scientists No.15-5561. 相似文献
40.
Subharmonic and DC responses in nonlinear ultrasound have been expected as a possible means of detecting closed cracks. Recently, it has been reported that subharmonics in a closed crack markedly increases above a certain input wave amplitude. Such a phenomenon is called "threshold behavior". However, the mechanism of threshold behavior has yet to be elucidated. To clarify this, we introduced adhesion force as a short-range force into the previous analytical model, which expresses the nonlinear contact vibrations of crack planes with intense ultrasound and provides a DC displacement as an approximation of the subharmonic response. Consequently, upward convex curves of displacement against input wave amplitude above the threshold were reproduced for the first time. The validity of the derived analytical solution is discussed by comparison with experimentally observed subharmonics. 相似文献