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排序方式: 共有370条查询结果,搜索用时 109 毫秒
91.
T. Kambara R. Schuch Y. Awaya T. Mizogawa H. Kumagai Y. Kanai H. Shibata K. Shima 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1992,22(2):451-456
We have measured the target thickness dependence ofK-vacancy production probabilities and total cross sections for 40.6 MeV Ar ions hitting Ca and Cu targets. The probabilities were measured as a function of the scattering angle between 0.13° and 1.4° by means of aK x-ray-particle coincidence. By integrating the measured probabilities over the impact parameter a significantly lower total cross section was obtained than the directly measured value. The maximum seen in the impact parameter dependent probability varies with decreasing target thickness towards the results obtained with molecular and atomic gas targets. From these observations a multiple collisionL-vacancy process prior to 2pπ-2pσ rational coupling is concluded. 相似文献
92.
Seiichiro Imamura Yo-ichi Taniguchi Yoshio Ikeda Saburo Hosokawa Hiroyoshi Kanai Hisanori Ando 《Reaction Kinetics and Catalysis Letters》2002,76(2):201-206
Three kinds of Ru/CeO2 catalysts were prepared. The mobility of the oxygen on Ru and their catalytic activity in the wet oxidation of acetic acid was investigated. Ru was present in the form of RuO2, and TPR experiment showed that the reaction, RuO2 + 2H2 Ru + 2H2O, took place in different temperature ranges depending upon the kind of the catalysts. The catalyst with easily reducible oxygen on Ru had high activity in wet oxidation, and the importance of the release of oxygen from Ru to the reactant was suggested. 相似文献
93.
Hiroyoshi Kanai Tatsuya Yoshikawa Tadahide Sone Yasuo Nishimura 《Reaction Kinetics and Catalysis Letters》2002,75(2):213-224
Highly dispersed V2O5/SiO2(CVD catalyst) was prepared by the reaction of vaporized VO(OPri)3 with silica at 293 K, whose process was followed by an IR technique. The rate of propylene photooxidation increased with an increase in V2O5 loading for CVD catalysts, but leveled off for impregnated ones. The CVD catalysts were characterized by XAFS and photoluminescence spectroscopy. 相似文献
94.
Takanori HayashiHiroyoshi Kanai Shinya YodoyaMasahito Oka Toshio Hayashi 《European Polymer Journal》2002,38(1):139-146
Two component random co-polypeptide hydrogels consisting of N-hydroxypropyl l-glutamine and l-alanine (Ala) or l-phenylalanine (Phe) were prepared by performing aminolysis reactions with 3-amino-1-propanol together with crosslinking reaction with 1,8-octamethylenediamine on hydrogels of the starting co-polymers consisted of γ-benzyl l-glutamate and Ala or Phe. The relationship between their bulk structure and properties was evaluated with regard to the swelling ratio in water (q), the rate of water vapor permeability (Vf), tensile properties, and enzymatic degradation behaviors of hydrogels in a pseudo-extracellular fluid (PECF). The tensile property of the hydrogels was highly dependent on q in PECF, and on the hydrophobicity of the side chains. A relationship was obtained between the Vf and q of hydrogels in PECF regardless of the differences in the nature of the side chains. Biodegradation of the hydrogels in vitro by bromelain indicated that degradation took place in bulk rather than on the surface, and that the rate of degradation was also highly dependent on q in the samples as well as on the hydrophobicity of the side chains of the samples. 相似文献
95.
Issei Kasahara Masami Kanai Masako Taniguchi Ayako Kakeba Noriko Hata Shigeru Taguchi Katsumi Goto 《Analytica chimica acta》1989
The singly charged complex anion bis[2-(5-bromo-2-pyridylazo)-5-(N-propyl-N-sulphopropylamino)phenolato]cobaltate(III) is intensely purple-violet and is stable over the pH range 1–13. Its absorption spectrum remains the same over this pH range. At pH2, it forms extractable ion pairs with long-chain quaternary ammonium ions and protonated alkylamines. Only the quaternary ammonium ions are extracted into chloroform at pH 11, hence separate extractions allow both types to be determined. The absorbance of the organic phase is measured at 594 nm. The apparent molar absorptivity is 7.0 × 104 l mol?1 cm?1. Calibration graphs for zephiramine, benzethonium and hexadecylpyridinium ions are linear over the range 0.1–2 × 10?6 M. The only interference found was from anionic surfactants. The method is applied to hair and fabric conditioners. 相似文献
96.
Yamasaki S Fujii K Wada R Kanai M Shibasaki M 《Journal of the American Chemical Society》2002,124(23):6536-6537
A general and mild catalytic allylation of carbonyl compounds, applicable to aldehydes, ketones, and imines is developed using allyltrimethoxysilane as the allylating reagent. The reaction proceeds smoothly with 1-10 mol % of CuCl and TBAT in THF at ambient temperature. Mechanism studies indicated that the copper alkoxide, allylfluorodimethoxysilane, and allyltrimethoxysilane are essential to promote the reaction efficiently. Preliminary extension of the reaction to the first catalytic enantioselective allylation of ketones using an allylsilane produced the product with 61% ee from acetophenone, using a CuCl-p-tol-BINAP-TBAT catalyst (15 mol %). 相似文献
97.
K. Matsuzaki T. Uryu T. Kanai K. Hosonuma T. Matsubara H. Tachikawa M. Yamada S. Okuzono 《Colloid and polymer science》1978,256(6):620-620
Ohne Zusammenfassung 相似文献
98.
99.
Balakrishna Kolli Sarada P. Mishra Akshaya K. Palai Tapan Kanai M. P. Joshi S. Raj Mohan T. S. Dhami L. M. Kukreja A. B. Samui 《Journal of polymer science. Part A, Polymer chemistry》2013,51(4):836-843
A series of dicyanomethylene‐substituted polymers having Y‐type molecular architecture were synthesized by Knoevenagel condensation reaction. The polymers were found to be soluble in organic solvents like tetrahydrofuran and chloroform. From gel permeation chromatography, the molecular weights of the polymers were found to be in the range of 15,300–33,800 g/mol. Thermal analysis showed that the polymers were stable up to 350 °C with glass transition temperature (Tg) in the range of 129–212 °C. These polymers were found to form good optical quality films. The order parameter was calculated to be in the range of 0.01–0.48. Atomic force microscopy indicated prominent morphology changes due to alignment of dipoles after poling. By using Nd:YAG laser of 1064 nm, angular dependence and temperature dependence of second‐harmonic generation intensity were investigated. The geometry optimization, shape of polymers, and restricted torsion angle between acceptor and donor substituents (push–pull system) were calculated. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
100.
M Takamura K Funabashi M Kanai M Shibasaki 《Journal of the American Chemical Society》2001,123(28):6801-6808
Full details of the first catalytic enantioselective Reissert-type reaction are described. Utilizing the Lewis acid-Lewis base bifunctional catalyst 5 or 6 (9 mol %), the Reissert products were obtained in 57 to 99% yield with 54 to 96% ee. Electron-rich quinolines produced better yields and enantioselectivities than electron-deficient substrates. Kinetic studies indicated that the reaction should proceed via the rate-determining acyl quinolinium formation, followed by the attack of a cyanide. The catalyst does not facilitate the first rate-determining step; however, it strongly facilitates the second cyanation step. The reaction was successfully applied to an efficient catalytic asymmetric synthesis of a potent NMDA receptor antagonist (-)-L-689,560. A key step is the one-pot process using the Reissert-type reaction from quinoline 1f, followed by stereoselective reduction of the resulting enamine 2f. This step gave the key intermediate 20 in 91% yield with 93% ee, using 1 mol % of 6. The enantiomerically pure target compound was obtained through 10 operations (including recrystallization) in total yield of 47%. Furthermore, 6 was immobilized to JandaJEL, and the resulting solid-supported catalyst 11 afforded 20 in a comparable yield to the homogeneous 6, but with slightly lower enantioselectivity. 相似文献