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41.
Jeroen W. Sprengers Marcel A. Duin Cornelis J. Elsevier 《Journal of organometallic chemistry》2003,679(2):149-152
A highly active and selective in situ formed platinum(N-heterocyclic carbene) catalyst for the hydrosilylation of styrene with triethylsilane is described, which unlike all other known hydrosilylation catalysts, selectively yields hydrosilylation products, but (almost) no dehydrogenative silylation products. 相似文献
42.
Summary Two reversed-phase LC systems were investigated by frontal analysis for the determination of linear chromatographic conditions,
as defined according to the isotherm concept. The Partisil ODS-3 bonded silica and the PRP-1 polystyrene-divinylbenzene resin
were used as stationary phases together withtrans-2-hexen-al as test solute and methanol-water mixtures as mobile phases. Particular attention was paid to the respective influence
of the two main parameters which may cause sorbent overloading, that is, the capacity factor (k′) and the solute concentration
in the mobile phase (Cm). Provided that k′Cm≤10−2 M, linear chromatographic behaviour was observed for both sorbents, the maximum capacities of which were found greater than
1mmolg−1. 相似文献
43.
A facile and practically applied protocol for synthesis of benzil derivatives using styrene and arene diazonium salts is reported. Pd(OAc)2/SeO2 catalytic system was found to be efficient for chemoselective synthesis of benzil. Selenium dioxide works well as an oxidant under milder reaction conditions. Moderate to very good yields of the desired products were obtained. 相似文献
44.
S. Munavalli D. K. Rohrbaugh G. W. Wagner F. R. Longo H. D. Durst 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4):781-789
Microwave catalyzed reaction of a neat mixture of styrene oxide and H-dimethylphosphonate furnished dimethyl methylphosphonate, trimethylphosphate, phenylacetaldehyde, 1-methoxy-2-phenylethanol, 1-phenylethleneglycol, cis- and trans-1,3-diphenylcyclobutanes, hydrogen 1-(2-phenylethyl)methylphosphinate, (1-phenylethyl)dimethylphosphonate, and (1-phenylethyl)dimethylphosphonate via free radical processes. 相似文献
45.
Shah A. Haque 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(7):827-833
Abstract A newly synthesized iniferter, N,N′-dimethyl-N,N′-bis(phenethyl)-thiuram disulfide, has been used in the free-radical living polymerization of styrene by a photochemical method. The low molecular weight (M w = 6000) difunctionalized polystyrene was used as a macroiniferter to photopolymerize methyl methacrylate, and was fractionated to obtain an A-B-A type block copolymer containing two poly(methyl methacrylate) units and one polystyrene unit in each block. The glass transition temperature, thermal stability, and 13C NMR of the block copolymer are discussed. 相似文献
46.
Mechanical properties of copolymers of 2-hydroxyethyl methacrylate with methyl methacrylate, ethyl methacrylate, and n-butyl methacrylate have been investigated using an Instron tensile tester. It was observed that the overall mechanical properties decrease as the ester alkyl group of alkyl methacrylate becomes bulkier. Biocompatibility of the copolymers was also investigated by implanting them subcutaneously in rats. 相似文献
47.
K. Sugiyama 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(1):13-30
The polymerization of acrylonitrile (AN) initiated by tetramethyl-2-tetrazene (TMT) and p-toluenesulfonic acid (TSA) in dimethylformamide (DMF) was studied. The polymerization was confirmed to proceed through a radical mechanism. The initial rate of polymerization R was expressed by the equation: Rp = k[TMT]0.6 [TSA]0.46 [AN]1.35. The overall activation energy for the polymerization was estimated as 20.7 kcal/mole. In the absence of monomer, the reaction of TMT with TSA was also studied kinetically by measuring the evolution of nitrogen. From these results and ESR measurement of the TMT/TSA system, a possible initiation mechanism is proposed. 相似文献
48.
In this work, styrene (St) based crosslinked polymers were prepared for removal of oil derivatives from aqueous solutions. Polyethylene glycol (600) dimethacrylate (PEG (600) DMA) was used as crosslinker in synthesis of styrene based crosslinked polymers, for the first time. The polymers were characterized by FTIR, SEM, elemental analysis and solvent (toluene, chloroform and fuel-oil) absorption capacities. The effects of different reaction parameters like crosslinker type, diluents amount and the presence of pore forming agent on the absorption properties of polymers were investigated. The polymers synthesized by using PEG (600) DMA have higher solvent absorption capacity than that of synthesized by using conventional crosslinker. Furthermore, the polymers synthesized in the presence of good diluents have higher absorption capacities. The addition of pore forming agent into the reaction medium has also improved the absorption rate of polymers. The absorption capacity of polymers in different solvents is in order of chloroform > toluene > fuel-oil. It was seen that oil derivatives can be removed efficiently from water by the St-PEG (600) DMA polymers. 相似文献
49.
A. KAIM 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(4):577-588
ABSTRACT The terminal and penultimate model reactivity ratios for the styrene-acrylonitrile monomer system in bulk have been investigated by the simplex and scanning method. It has been shown that Mayo-Lewis equation has an unique solution when determining the reactivity ratios according to the terminal model while for the penultimate model the non-uniqueness in determination of the reactivity ratios has been found. The numerical values of the penultimate r-parameters calculated with the simplex method depend on the initial guess for r-parameters. Several sets of penultimate reactivity ratios for the styrene-acrylonitrile system in bulk have been found to be equal from mathematical point of view. The reactivity ratios with comparable standard deviation have an equivalent graphical representation on the copolymerization diagragm. It has been also confirmed that the penultimate model is a more appropriate of the models considered to describe the variation of the copolymer composition with the monomer feed. Taking into account previous results for the styrene-methyl methacrylate system in bulk it is thereby assumed that the occurrence non-uniqueness in determination of the penultimate model reactivity ratios does not depend on the monomer system. 相似文献
50.
《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10):1057-1080
Abstract Copolymers involving styrene and homologues of alkyl methacrylates (viz., methyl, ethyl, and butyl methacrylates) were synthesized at 60°C by employing a mixture of n‐butylamine and carbontetrachloride as charge transfer (CT) initiators in dimethyl sulphoxide medium. The CT complex was characterized by UV spectroscopy while the respective copolymers were characterized by employing infrared (IR) and 1H NMR spectroscopy. The copolymer compositions were determined by using 1H NMR spectroscopy and the reactivity ratios were computed by Fineman–Ross (F–R) and Kelen–Tudos (K–T) methods. The reactivity ratios of Sty‐MMA and Sty‐EMA copolymers indicate that higher level of styrene is incorporated in the copolymer. On the other hand the Sty‐BMA system exhibits different behavior. The higher value of r 2 is obtained denoting that BMA is more active than styrene and hence, more BMA is present in the copolymer chain. In Sty‐MMA and Sty‐BMA systems, the product of r 1 and r 2 is greater than 1, representing the formation of high degree of random copolymers. However, in the case of Sty‐EMA, the product of r 1 and r 2 is less than 1 indicating the formation of alternating copolymer. 相似文献