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Ohne Zusammenfassung 相似文献
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Iványi T Vander Heyden Y Visky D Baten P De Beer J Lázár I Massart DL Roets E Hoogmartens J 《Journal of chromatography. A》2002,954(1-2):99-114
This paper focuses on the classification or differentiation of RP-HPLC columns based on measured chromatographic properties. A chemometric study has been conducted on a published data set consisting of 85 RP-HPLC columns and on a data set consisting of 47 self-tested columns. Principal component analysis enables determination of the number of parameters necessary for a rational differentiation. The results show that reducing the number of parameters for such differentiation still allows classification of the columns just as a higher number did. It is shown that three test parameters produce a classification similar to that obtained with five parameters. 相似文献
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Emilio J. González Patricia F. Requejo Ángeles Domínguez Eugénia A. Macedo 《Journal of solution chemistry》2013,42(4):746-763
In this study, densities and speeds of sound were measured over the whole composition range, at T = (298.15, 303.15 and 308.15) K and p = 0.1 MPa, for the binary systems of ethanol, or 1-propanol, or 2-propanol and 1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide, or 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide. The density and speed of sound data were used to calculate the corresponding excess molar volumes and excess molar isentropic compressions, which were fitted with the Redlich–Kister equation. From the obtained results, a discussion was carried out in terms of interactions and structure factors in these binary mixtures. 相似文献
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Fernando P. Carvalho João M. Oliveira M. Malta M. Eugénia Lemos 《Journal of Radioanalytical and Nuclear Chemistry》2014,299(1):119-125
During the past century extensive uranium mining took place in Portugal for radium and uranium production. One such uranium mine was the Boco Mine, in operation during the 1960s and 70s. Mining waste and open pits were left uncovered since mine closure. During the nineties a quarry for sand extraction was operated in the same site and water from a local stream was extensively used in sand sieving. Downstream the mine area, agriculture soil is used for cattle grazing. Water from the stream, water wells, soil, pasture and sheep meat were now analyzed for radionuclides of uranium natural series. The U-series radionuclide 226Ra was generally the highest in concentrations especially in soil, pasture, and in internal organs of sheep. 226Ra concentrations were 1,093 ± 96 Bq/kg (dry weight, dw) in soil, 43 ± 3 Bq/kg (dw) in pasture, and 193 ± 84 mBq/kg (wet weight, ww) in muscle tissue of sheep. Other sheep internal organs displayed much higher 226Ra concentrations, such as the brain and kidneys with 1,850 ± 613 mBq/kg (ww) and 6,043 ± 6,023 mBq/kg (ww), respectively. Results of analyses of tissue samples from sheep grown in a comparison area were 2 to 16 times lower, depending on the organ. Absorbed radiation doses for internal organs were computed and may exceed 5.2 mGy/y in the case of kidneys, near three times higher than in animals from the reference area, but below the threshold for biological effects. Radionuclide transfer in the terrestrial food chain and radiation exposure of the human population is discussed. 相似文献
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Mônica Siqueira Ferreira Diogo Noin de Oliveira Rosimeire Nunes de Oliveira Silmara Marques Allegretti Aníbal Eugênio Vercesi Rodrigo Ramos Catharino 《Journal of mass spectrometry : JMS》2014,49(1):86-92
Schistosomiasis is a neglected disease with large geographic distribution worldwide. Among the several different species of this parasite, S. mansoni is the most common and relevant one; its pathogenesis is also known to vary according to the worms' strain. High parasitical virulence is directly related to granulomatous reactions in the host's liver, and might be influenced by one or more molecules involved in a specific metabolic pathway. Therefore, better understanding the metabolic profile of these organisms is necessary, especially for an increased potential of unraveling strain virulence mechanisms and resistance to existing treatments. In this report, MALDI‐MSI and the metabolomic platform were employed to characterize and differentiate two Brazilian S. mansoni strains: males and females from Belo Horizonte (BH) and from Sergipe (SE). By performing direct analysis, it is possible to distinguish the sex of adult worms, as well as identify the spatial distribution of chemical markers. Phospholipids, diacylglycerols and triacylglycerols were located in specific structures of the worms' bodies, such as tegument, suckers, reproductive and digestive systems. Lipid profiles were found to be different both between strains and males or females, giving specific metabolic fingerprints for each group. This indicates that biochemical characterization of adult S. mansoni may help narrowing‐down the investigation of new therapeutic targets according to worm composition, molecule distribution and, therefore, aggressiveness of disease. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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This paper describes a new multiobjective interactive memetic algorithm applied to dynamic location problems. The memetic
algorithm integrates genetic procedures and local search. It is able to solve capacitated and uncapacitated multi-objective
single or multi-level dynamic location problems. These problems are characterized by explicitly considering the possibility
of a facility being open, closed and reopen more than once during the planning horizon. It is possible to distinguish the
opening and reopening periods, assigning them different coefficient values in the objective functions. The algorithm is part
of an interactive procedure that asks the decision maker to define interesting search areas by establishing limits to the
objective function values or by indicating reference points. The procedure will be applied to some illustrative location problems. 相似文献
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