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81.
Diaryl and arylalkyl ketones such as acetophe-none, p-methylacetophenone, propiophenone, and benzophe-none as well as diaryl and arylalkyl secondary alcohols such as 1-phenylethanol and benzhydrol were effectively hydrogenated to hydrocarbons (methylene) by NaBH4, in combination with A1C13. 相似文献
82.
Charge-transfer-induced decomposition (CTID) of bicyclic dioxetanes 1b-d bearing a 3-hydroxylphenyl moiety substituted with a benzothiazol-2-yl group at the 2-, 6-, or 5-position was investigated, and their chemiluminescence properties were compared to each other, based on those for a 4-benzothiazolyl analogue 1a. Dioxetanes 1c and 1d underwent CTID to give the corresponding oxido anions of keto esters 8c or 8d in the singlet excited state with high efficiencies similarly to the case of 1a. On the other hand, 1b showed chemiluminescence with quite low efficiency, though it gave exclusively keto ester 2b. The marked decline of chemiluminescence efficiency for 1b was attributed to 1b mainly being decomposed to 8b through a radiationless pathway, in which intramolecular nucleophilic attack of nitrogen in the benzothiazolyl group to dioxetane O-O took place to give cyclic intermediate cis-11. 相似文献
83.
A series of microporous lanthanide-organic framework enantiomers, Ln(BTC)(H(2)O)·(DMF)(1.1) (Ln = Y 1a, 1b; Tb 2a, 2b; Dy 3a, 3b; Er 4a, 4b; Yb 5a, 5b, BTC = 1,3,5-benzenetricarboxylate; DMF = N,N-dimethylformamide) with unprecedented (6,6)-connected topology have been prepared and characterized. All these compounds exhibit very high thermal stability of over 450 °C. The pore characteristics and gas sorption properties of these compounds were investigated at cryogenic temperatures by experimentally measuring nitrogen, argon, and hydrogen adsorption/desorption isotherms. The studies show that all these compounds are highly porous with surface areas of 1080 (1), 786 (2), 757 (3), 676 (4), and 774 m(2)/g (5). The amounts of the hydrogen uptakes, 1.79 (1), 1.45 (2), 1.40 (3), 1.51 (4), and 1.41 wt % (5) at 77 K (1 atm), show their promising H(2) storage performances. These porous materials with considerable surface areas, high voids of 44.5% (1), 44.8% (2), 47.7% (3), 44.2% (4), and 45.7% (5), free windows of 6-7 ?, available exposed metal sites and very high thermal stability can be easily prepared on a large scale, which make them excellent candidates in many functional applications, such as, gas storage, catalysis, and so on. 相似文献
84.
This study addresses Bezout equations over bivariate polynomial matrices, where the relationship between two variables is described by a real entire function. This paper proposes a solution method that makes optimal use of minor primeness to reduce such Bezout equations to simple equations over univariate scalar polynomials. The proposed solution method requires only matrix calculations, thus making it very useful, especially in the absence of modern computer algebra systems. 相似文献
85.
Kojima Y Matsumoto M Kawai Y Haga T Ohba N Miwa K Towata S Nakamori Y Orimo S 《The journal of physical chemistry. B》2006,110(19):9632-9636
Lithium hexahydridoaluminate Li(3)AlH(6) and lithium amide LiNH(2) with 1:2 molar ratio were mechanically milled, yielding a Li-Al-N-H system. LiNH(2) destabilized Li(3)AlH(6) during the dehydrogenation process of Li(3)AlH(6), because the dehydrogenation starting temperature of the Li-Al-N-H system was lower than that of Li(3)AlH(6). Temperature-programmed desorption scans of the Li-Al-N-H system indicated that a large amount of hydrogen (6.9 wt %) can be released between 370 and 773 K. After initial H(2) desorption, the H(2) absorption and the desorption capacities of the Li-Al-N-H system with a nano-Ni catalyst exhibited 3-4 wt % at 10-0.004 MPa and 473-573 K, while the capacities of the system without the catalyst were 1-2 wt %. The remarkably increased capacity was due to the fact that the kinetics was improved by addition of the nano-Ni catalyst. 相似文献
86.
Compound [Fe2(μ-CO)2(CO)2(η5-C9H7)2] (1) reacts with aryllithium reagents, ArLi (Ar = C6H5, p-CH3C6H4, p-CF3C6H4) followed by alkylation with Et3OBF4 to give the diindenyl-coordinated diiron bridging alkoxycarbene complexes [Fe2{μ-C(OC2H5)Ar}(μ-CO)(CO)2(η5-C9H7)2] (2, Ar = C6H5; 3, Ar = p-CH3C6H4, 4, Ar = p-CF3C6H4). Complex 4 reacts with HBF4 · Et2O at low temperature to yield cationic bridging carbyne complex [Fe2(μ-CC6H4CF3-p)(μ-CO)(CO)2(η5-C9H7)2]BF4 (5). Cationic 5 reacts with NaBH4 in THF at low temperature to afford diiron bridging arylcarbene complex [Fe2{μ-C(H)C6H4CF3-p}(μ-CO)(CO)2(η5-C9H7)2] (6). The reaction of 5 with NaSC6H4CH3-p under the similar conditions gave the bridging arylthiocarbene complex [Fe2{μ-C(C6H4CF3-p)SC6H4CH3-p}(μ-CO)(CO)2(η5-C9H7)2] (7). Complex 5 can also react with carbonylmetal anionic compounds Na[M(CO)5(CN)] (M = Cr, Mo, W) to produce the diiron bridging aryl(penta-carbonylcyanometal)carbene complexes [Fe2{μ-C(C6H4CF3-p)NCM(CO)5}(μ-CO)(CO)2(η5-C9H7)2] (8, M = Cr; 9, M = Mo; 10, M = W). The structures of complexes 4, 6, 7, and 10 have been established by X-ray diffraction studies. 相似文献
87.
Nobuko Oikawa 《Journal of Sol-Gel Science and Technology》2000,19(1-3):729-732
Near-Infrared spectroscopic studies on varying water contents in the sol-gel system using methyltriethoxysilane and tetraethoxysilane were performed. Water and silanol were clearly distinguished from alcoholic OH groups in the spectra. The change of water and silanol contents in acetone or 2-butanone was larger than those in alcoholic solvents. 1H nuclear magnetic resonance spectroscopic measurement showed that hydrolysis and condensation reaction in methanol is faster than those in 2-butanone. 相似文献
88.
Micrometer-sized, hemispherical polymer particles were prepared as a result of cleavage of spherical Janus poly(methyl methacrylate) (PMMA)/polystyrene (PS) composite particle by treating particles with acetone/water solutions. The original PMMA/PS composite particles were prepared by the slow evaporation of toluene from homogeneous PMMA/PS/toluene droplets dispersed in aqueous solution of sodium dodecyl sulfate in advance. Appropriate molecular weights of PMMA and PS were necessary for occurrence of the cleavage of the Janus composite particle, resulting in PMMA and PS hemispherical particles. The cleavage depended on the composition of the acetone/water solution, which was explained by selective solvent absorption into the polymer phases. The results strongly support the cleavage mechanism of Janus composite polymer particles that had been proposed earlier. 相似文献
89.
Hisashi Saitoh Hisako K. Ijuin Nobuko Watanabe Masakatsu Matsumoto 《Helvetica chimica acta》2013,96(9):1704-1713
When treated with LiNiPr2 (LDA) at ?78°, 1‐[(methylsulfanyl)methyl]‐2‐[(1Z,3E)‐4‐phenylbuta‐1,3‐dien‐1‐yl]benzene easily cyclized to form benzocycloheptenyl anion, which successively underwent intramolecular nucleophilic substitution to give a cyclopropanaphthalene. Similar LDA‐mediated cyclization also occurred for 4‐phenyl‐ or 4‐methyl‐substituted 1‐[2‐(methoxymethyl)phenyl]buta‐1,3‐dienes to furnish the corresponding benzocycloheptenes and cyclopropanaphthalenes. A 4‐tert‐butyl analog also underwent LDA‐mediated cyclization to give a benzocycloheptene, but not a cyclopropanaphthalene. 相似文献
90.
Diana C. Rambaldi Federica Pozzi Nobuko Shibayama Marco Leona Frank D. Preusser 《Journal of Raman spectroscopy : JRS》2015,46(11):1073-1081
Madder has been used as a textile dye and pigment in works of art since antiquity. Madder dyes from different botanical species are characterized by different series of anthraquinone derivatives. The occurrence of one or more of these compounds in various relative amounts may provide a useful indication of the plant species used to obtain the dye. In this work, surface‐enhanced Raman spectroscopy (SERS) was applied to the analysis of textile fibers dyed with madder from two different botanical species, Oldenlandia umbellata L. and Rubia tinctorum L. The resulting SERS spectra were interpreted in light of the actual composition of the madder dyes as determined by high‐performance liquid chromatography. Interestingly, the SERS spectra were found to exhibit very distinctive spectral features depending on the different anthraquinone derivatives present in the dyes. In particular, the SERS spectrum of O. umbellata L. was found to match the spectrum of alizarin, while the SERS spectrum of R. tinctorum L. was surprisingly dominated by signals due to the less studied anthraquinone compound pseudopurpurin. With this study, we demonstrate that SERS spectra may offer valuable information regarding the major coloring constituents present in different madder species. Moreover, our work shows that not only can SERS be used successfully to differentiate among closely related anthraquinone derivatives, but also that this technique is particularly suitable for the detection of pseudopurpurin, leading to the identification of this compound in a number of works of art. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献