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101.
Ultrafast photosynthetic reduction of elemental sulfur by Au nanoparticle-loaded TiO2 总被引:1,自引:0,他引:1
Kiyonaga T Mitsui T Torikoshi M Takekawa M Soejima T Tada H 《The journal of physical chemistry. B》2006,110(22):10771-10778
Nanometer-sized gold particles with varying mean size from 3.2 to 12.2 nm were loaded on the surfaces of TiO2 particles in a highly dispersed state with the loading amount maintained constant (0.46 +/- 0.02 mass %) using the deposition-precipitation method. Light irradiation (lambda(ex) > 300 nm) to a deaerated ethanol TiO2 particle suspension containing elemental sulfur (S8) led to the energetically uphill reduction of S8 to H2S. It has been found that this reaction is dramatically enhanced with such a low level of Au loading on TiO2 and that the zero-order rate constant of reaction increases with decreasing mean size of Au nanoparticles (d). The effects of reaction parameters (substrate concentration, light intensity, temperature) on the rate of reaction were studied to infer the essential reaction mechanism. Further, a kinetic analysis has led to a conclusion that the increase in the rate of reaction with decreasing d results from the improvement of the charge separation efficiency. 相似文献
102.
A combination of CBr4–Ph3P, a non-metal method, enables us to carry out aerobic photo-oxidation of alcohols and aromatic methyl groups to the corresponding carboxylic acids under irradiation of vis from a general-purpose fluorescent lamp. Aliphatic primary- and secondary alcohols, benzyl alcohols, and methyl groups at the aromatic nucleus generally afforded the carboxylic acids directly in good to high yield. 相似文献
103.
Tanatani A Yokoyama A Azumaya I Takakura Y Mitsui C Shiro M Uchiyama M Muranaka A Kobayashi N Yokozawa T 《Journal of the American Chemical Society》2005,127(23):8553-8561
Poly(p-benzamide)s 1 bearing a chiral side chain on the nitrogen atom were synthesized by chain-growth polycondensation methodology. The polyamides exhibited well-defined molecular weights with narrow polydispersities. Solutions of the polyamides in several organic solvents (CH(3)CN, CHCl(3), and CH(3)OH) showed dispersion type CD signals characteristic of coupled-oscillator and much larger as compared with the corresponding monomer. The CD signals were dependent on the temperature and molecular weight of the polyamides but independent of the solvent, as far as examined. An exciton model analysis of the absorption and CD spectra provided a clear-cut picture for the secondary structure of these polyamides in solution that the N-alkylated poly(p-benzamide)s possess a right-handed helical conformation ((P)-helix). In the solid states, the results of X-ray crystallographic analysis of 4-(methylamino)benzoic acid oligomers substantiated that they have a helical conformation with three monomer units per turn. 相似文献
104.
Thermal decomposition of ammonium uranates precipitated from uranyl nitrate solutions on addition of aqueous ammonium hydroxide under various conditions has been examined by thermogravimetry (TG), differential thermal analysis (DTA), infrared spectroscopy and X-ray diffraction study. The TG curves of all precipitates show the weight-loss corresponding to the calculated value as UO3·NH3·H2O. The DTA curves of the precipitates give the endotherms at about 130, 210 and 590 °C and the exotherms at 340–420 °C. As a result, it is found that ammonium uranates thermally decompose to amorphous UO3 at about 400 °C, and transform to U3O8 via β-UO3. 相似文献
105.
106.
1,3-Butadiene-2-carboxylates were treated with a titanium(II) alkoxide reagent, Ti(O-i-Pr)4/2i-PrMgCl, to generate diene-titanium alkoxide complexes, the presence of which was verified by hydrolysis and deuteriolysis to give the corresponding monoolefins or their bis-deuterated counterpart. These diene complexes underwent successive addition to an aldehyde (as the first electrophile) and iodine (as the second one) in a highly regio- and stereoselective manner to give the corresponding iodo alcohol. Optically active 1,3-butadiene-2-carboxylates afforded the same adducts of high asymmetric induction. Besides these electron-deficient dienes, electron-rich 2-siloxy-1,3-butadienes also participated in the formation of the titanium complex, which led to the preparation of functionalized enol silyl ethers through regio- and stereoselective coupling with carbonyl compounds and hydrolytic workup. 相似文献
107.
Wasaburo Kawai Taichi Ichihashi 《Journal of polymer science. Part A, Polymer chemistry》1974,12(5):1041-1048
New routes for copolymerization of carbon monoxide with styrene or vinyl chloride were found by emulsion polymerization (nonionic or ionic emulsifier). These procedures yielded copolymers containing carbonyl groups even at high conversion. These carbonyl-containing polyketones were photoirradiated in solvent. In carbon monoxide—styrene copolymer of high molecular weight, the viscosity change produced by photoirradiation was especially remarkable, while in carbon monoxide—vinyl chloride copolymer no pronounced change in viscosity was observed, even at high contents of carbonyl group. 相似文献
108.
Kazuhiro Maruyama Tetsuo Otsuki Kiichiro Mitsui Masahiro Tojo 《Journal of heterocyclic chemistry》1980,17(4):695-700
Anthra[2,1-b]furan, anthra[2,1-b]benzo[d]furan, anthra[2,1-b]thiophene, anthra[1,2-b]thiophene, anthra[2,1-b]benzo[d]thiophene, anthra[2,1-b]pyrrole and naphtho[2,3-c]carbazole derivatives were synthesized in fairly good yields by a one-pot photocycloaddition reaction of 2,3-disubstituted 1,4-naphthoquinone with 1,1-diarylethylene. This is the first reported synthesis of these aromatic compounds. 相似文献
109.
Hiroshi Mitsui Fumio Hosoi Miyuki Hagiwara Tsutomu Kagiya 《Journal of polymer science. Part A, Polymer chemistry》1968,6(10):2881-2888
The effects of acetylene on the γ-radiation-induced polymerization of ethylene were studied from the viewpoint of the gaseous products and polymer structure. The experiments were carried out under a pressure of 400 kg/cm2; the temperature was 30°C; the does rate was 1.1 × 105 rad/hr; and the acetylene content was 0–20%. The solid polymer was obtained in the polymerization of ethylene containing 2.2% acetylene, while the monomer containing 19.7% acetylene gave a yellowish viscous oil. The polymer yield and molecular weight decreased remarkably with acetylene content. The main gaseous product was hydrogen, and trace amounts of butane, butene-1, butadiene-1,3, and benzene and its derivatives were also observed. The rate of formation of hydrogen was almost independent of acetylene content and there was no difference in acetylene contents before and after the irradiation was found. The infrared spectra of the polymers showed the presence of vinylidene, trans-vinylene, and terminal vinyl unsaturations, 1,4-disubstituted benzene, and carbonyl groups. The contents of trans-vinylene, terminal vinyl, and methyl groups increased with acetylene content, and that of vinylidene was independent of acetylene content. The monomer reactivity ratios of ethylene and acetylene were evaluated as 45.5 and 66.0, respectively. On the basis of the results, the effects of acetylene on the γ-radiation-induced polymerization of ethylene were discussed. 相似文献
110.
Hiroshi Mitsui Sueo Machi Miyuki Hagiwara Fumio Hosoi Tsutomu Kagiya 《Journal of polymer science. Part A, Polymer chemistry》1967,5(11):2731-2743
The effects of oxygen on the γ-radiation-induced polymerization of ethylene were studied at a temperature of 30°C.; the pressure was 400 kg./cm.2, the dose rate was 1.9 × 105 rad/hr.; and oxygen content was from 1–2000 ppm. The main product was solid polymer, and no liquid product was found. The gaseous products were hydrogen, acetylene, higher hydrocarbons, carbon dioxide, aldehydes, and acids. Several kinds of carbonyls similar to those formed in γ-ray oxidized polyethylene were observed in the polymer. The polymer yield and the degree of polymerization decreased markedly with increasing oxygen content, while the amount of carbonyls in the polymer increased. The number of moles of polymer chain and the amounts of hydrogen and acetylene were found to be almost independent of the oxygen content. The polymerization of pure ethylene was not affected by carbon dioxide and formic acid. On addition of acetaldehyde, the polymer yield and the degree of polymerization decreased markedly, while the number of moles of polymer chain increased. In the polymerization of ethylene containing oxygen, both the rate of oxygen consumption and the carbonyl content of the polymer increased, while the inhibition period decreased by the addition of acetaldehyde. It was found that the degree of polymerization after the inhibition period is almost independent of the reaction time in the presence of acetaldehyde, while it increases with the time in the absence of acetaldehyde. 相似文献