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排序方式: 共有240条查询结果,搜索用时 31 毫秒
61.
62.
Luca Piemontese Salvatore Faliti Giuseppe Carbonara Antonio Laghezza Paolo Tortorella Fulvio Loiodice 《Chromatographia》2009,70(9-10):1327-1333
The LC enantiomeric separation of several dual PPARα/γ agonists on the commercially available Chiralcel OD and Chiralpak AD columns has been evaluated in normal phase mode using a mobile phase consisting in a mixture of n-hexane, 2-propanol and trifluoroacetic acid at constant volume ratio. Most compounds were separated as underivatized acids without requiring time consuming analysis. Some complementary selectivity was evidenced on the two investigated chiral stationary phases related to the different accessibility of the active sites of the helical cavities. Additional information on the chiral recognition mechanism were deduced from the chromatographic behaviour of some selected methyl esters. 相似文献
63.
Fulvio Rossi Fabrizia Fabrizi de Biani Piero Zanello Piotr Buchalski 《Journal of Solid State Electrochemistry》2009,13(10):1505-1510
A collection of nickelocene and cobaltocene analogs with one or two nickelafluorenyl rings has been recently synthesized starting
from 9-nickelafluorenyllithium complex. The redox ability of the whole series of derivates has been investigated by electrochemical
techniques, and the nature of the frontier orbitals responsible for the electron transfer activity of this class of compounds
has been supported by extended Hückel calculations.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
64.
Donfack JH Simo CC Ngameni B Tchana AN Kerr PG Finzi PV Vidari G Giardina S Buonocore D Ngadjui BT Moundipa PF Marzatico F 《Natural product communications》2010,5(10):1607-1612
Free radicals, in particular radical oxygen species (ROS), play an important role in the aetiology and pathogenesis of various diseases. Current research in many countries focuses on the use of local medicinal plants as a promising source of liver protective agents. This paper describes the hepatoprotective effects of the methanol extract and four isolated compounds from Ficus chlamydocarpa on CCl4-induced liver damage, as well as the possible antioxidant mechanisms involved in this protection. The DPPH test, along with the beta-Carotene-Linoleic Acid Model System and Ferric-Reducing Antioxidant Power assays, as well as the inhibition of microsomal lipid peroxidation were used to measure radical-scavenging and antioxidant activities. Pretreatment of rats with the methanol extract of F. chlamydocarpa before CCl4 administration, significantly prevented serum increase of hepatic enzyme markers, glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT), in a dose-dependent manner. The hepatoprotection was also associated with a significant enhancement in hepatic reduced glutathione (GSH) and a marked decrease of liver malondialdehyde (MDA). Among the four compounds 1-4, isolated from the methanol extract, alpha-amyrin acetate (1) and luteolin (4) showed a significant hepatoprotective activity, as indicated by their ability to prevent liver cell death and lactate dehydrogenase (LDH) leakage during CCl4 intoxication. 相似文献
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Paolo Linda Cynthia Ebert Mara Lovrecich Fulvio Rubessa 《Journal of heterocyclic chemistry》1984,21(1):271-272
The hydroxide ion catalyzed hydrolysis of indole-1-carboxamide and indole-1-(N,N-dimethyl)carboxamide has been studied in water at 60.0° and [OH−] concentration between 0.3--2.4N. The rate constants of formation of the tetrahedral intermediate are strongly increased by N-substitution with a heteroaromatic ring in comparison with simple amides. Carbamazepine, (5H-dibenz[b,f]azepine)-5-carboxamide, a potent anticonvulsant drug, is particularly stable under these conditions. 相似文献
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Alessandro Cagnina Sandro Campestrini Fulvio Di Furia Patrizia Ghiotti 《Journal of molecular catalysis. A, Chemical》1998,130(3):751-231
As reported in previous papers, the oxidation of ethylbenzene with Ph4PHSO5 catalyzed by Mn(TMP)Cl in the presence of nitrogen bases in 1,2-dichloroethane homogeneous solution affords fair yields (up to 80%) of oxygenated products. Acetophenone is the major product together with minor amounts of 1-phenylethanol ([ketone]/[alcohol]6). In this paper we report further observations concerning this system. In particular we find that a similar products distribution is observed when soluble Co(II) or Fe(II) species, i.e. acetylacetonate derivatives, are used instead of the manganese porphyrin. On the other hand for these compounds, which are catalysts of radical reactions, the product distribution is determined by a remarkably larger reactivity of the alcohol initially formed compared with that of the alkane (kR–OH/kR–H200). The product distribution for the Mn(TMP)Cl catalysis cannot be rationalized on the same basis. Direct experiments show that the reactivity of the two substrates is similar (kR–OH/kR–H2–6) thus suggesting that a mechanism different from the simple radical hydrogen atom abstraction is taking place. The dependence of the chemioselectivity of hydrocarbon oxidation on the nature of the manganese porphyrin employed and of a number of additives indicates that the product distribution is mainly determined by the relevance of the association of the alcohol intermediate to the catalyst prior to the second oxidation step leading to ketone. Two different rho Hammett's values are obtained for ethylbenzenes oxidation depending on the method employed for the measurement of reaction rates, i.e. by separate or by competitive experiments thus providing further mechanistic information on the association of the substrates to the oxo-species. 相似文献