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排序方式: 共有229条查询结果,搜索用时 15 毫秒
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Joana Sousa Gilberto Alves Ana Fortuna Angelina Pena Celeste Lino Amílcar Falcão 《Biomedical chromatography : BMC》2011,25(5):535-541
A simple and fast liquid chromatographic method coupled with fluorescence detection (LC‐FD) is reported, for the first time, for the simultaneous quantification of norfloxacin (NOR), ciprofloxacin (CIP) and lomefloxacin (LOM) in human plasma, using levofloxacin as internal standard (IS). Sample preparation consists of a single‐step precipitation of plasma proteins followed by vortex‐mixing and centrifugation. Chromatographic separation was achieved within 7 min on a reversed‐phase C18 column with a mobile phase consisting of 0.1% aqueous formic acid (pH = 3.0, triethylamine)–methanol (82:18, v/v) pumped isocratically at 1.2 mL/min. The detector was set at excitation/emission wavelengths of 278/450 nm. Calibration curves were linear (r2 ≥ 0.994) in the range of 0.02–5.0 µg/mL, and the limit of quantification was established at 0.02 µg/mL for all analytes (NOR, CIP and LOM). The overall precision did not exceed 8.19% and accuracy was within ±10.91%. NOR, CIP and LOM were extracted from human plasma with an overall mean recovery ranged from 90.1 to 111.5%. No interferences were observed at the retention times of the analytes and IS. This novel LC‐FD method enables the reliable determination of NOR, CIP and LOM in a single chromatographic run, which may be suitable to support human pharmacokinetic‐based studies with those antimicrobial agents. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Frontispiece: Combined Spectroscopic and Electrochemical Detection of a NiI⋅⋅⋅HN Bonding Interaction with Relevance to Electrocatalytic H2 Production 下载免费PDF全文
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Catheline A Vallés C Drummond C Ortolani L Morandi V Marcaccio M Iurlo M Paolucci F Pénicaud A 《Chemical communications (Cambridge, England)》2011,47(19):5470-5472
Thermodynamics drive the spontaneous dissolution of a graphite intercalation compound (GIC) KC(8) in NMP to form stable solutions. Reduction potential of graphene is measured at +22 mV vs. SCE. Single layer graphene flakes (ca. 1 μm(2)) have been unambiguously identified by electron diffraction. 相似文献
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Miroslaw Pluta Marius Murariu Amália Da Silva Ferreira Michael Alexandre Andrzej Galeski Philippe Dubois 《Journal of Polymer Science.Polymer Physics》2007,45(19):2770-2780
Starting from calcium sulfate (gypsum) as fermentation by‐product of lactic acid production process, high performance composites have been produced by melt‐blending polylactide (PLA, L/D isomer ratio of 96:4) and β‐anhydrite II (AII) filler, that is, calcium sulfate hemihydrate previously dehydrated at 500 °C. Characterized by attractive mechanical and thermal properties due to good filler dispersion throughout the polyester matrix, these composites are interesting for potential use as biodegradable rigid packaging. Physical characterization of selected composites filled with 20 and 40 wt % AII has been performed and compared to processed unfilled PLA with similar amorphous structure. State of dispersion of the filler particles and interphase characteristic features have been investigated using light microscopy (LM) and scanning electron microscopy (SEM). Addition of AII did not decrease PLA thermal stability as revealed by thermogravimetry analyses (TGA) and allowed reaching a slight increase of PLA crystallizability during melt crystallization and upon heating from the glassy, amorphous state (DSC). It was found by thermomechanical measurements (DMTA) that the AII filler increased pronouncedly storage modulus (E′) of the composites in comparison with PLA in a broad temperature range. The X‐ray investigations showed stable/unchanged crystallographic structure of AII during processing with molten PLA and in the composite system. The notable thermal and mechanical properties of PLA–AII composites are accounted for by the good filler dispersion throughout the polyester matrix confirmed by morphological studies, system stability, and favorable interactions between components. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2770–2780, 2007 相似文献
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Jaegler Hugo Pointurier Fabien Onda Yuichi Angulo Jaime F. Griffiths Nina M. Moureau Agnes Faure Anne-Laure Marie Olivier Hubert Amélie Evrard Olivier 《Journal of Radioanalytical and Nuclear Chemistry》2019,322(1):57-66
An aqueous biphasic system has been used for selective extraction of U(VI) ions from Th(IV), Sm(III) and Ce(III). Role of different biomolecules like morin, catechin, hesperidin and 4-hydroxycoumarin have been studied. Morin serves as the best reagent when citrate ions are used as a masking agent. Citrate forms stronger complexes with the other metal ions than morin thereby restricting their extractions. Contrarily, U(VI) forms a stronger complex with morin than citrate and is selectively extracted under the same conditions. It was also observed that morin can act as a spectrophotometric reagent for ratiometric detection and analysis of U(VI) ions.
相似文献28.
Evandro A. de Morais Luis V.A. Scalvi Alberto A. Cavalheiro Américo Tabata José Brás B. Oliveira 《Journal of Non》2008,354(42-44):4840-4845
Some very relevant optical, electrical, and structural properties of SnO2 doped with rare-earth ions Er3+ and Eu3+ are presented. Films are produced by the sol–gel-dip coating process, and may be described as a combination of nanoscopic dimension crystallites (about 3–10 nm) with their respective intergrain potential barriers. The Er3+ and Eu3+ ions are expected to act as acceptors in SnO2, which is a natural n-type conductor, inducing a high degree of charge compensation. Electron trapping and emission spectra data are presented and are rather distinct, depending on the location of the rare-earth impurity. This behavior allows the identification of two distinct centers: located either in the SnO2 lattice or segregated at the particles surface. Based on a model for thermally activated cross-section defects, the difference between the capture energy of the photo-excited electron and the intergrain potential barrier is evaluated, leading to distinct values for high and low symmetry sites. A higher distortion in the lattice of undoped SnO2 and SnO2:Eu (1 at.%) was evaluated from Rietveld refinements of X-ray diffraction data. This was confirmed by Raman spectra, which are associated with the particles size and disorder. By comparing the samples with the same doping concentration, it was found that this disorder is higher in Eu-doped SnO2 than in Er-doped SnO2, which is in agreement with a higher energy for the lattice relaxation in the trapping process by Eu3+ centers. 相似文献
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