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51.
Summary Gradient reversed-phase liquid chromatography was examined with a view to using it as a separation technique for the speciation of vanadyl and nickel porphyrins in oil extracts. Poor separations were obtained when precipitation of the sample constituents occurred in the starting mobile phase. The reasons for the precipitation phenomena were found to be highly complex. Mixed crystal formation, slow dissolution kinetics and saturation may influence the elution behaviour of species present in the oil extracts. When precipitation was avoided the separation of the vanadyl porphyrins was significantly improved. Thus far, no satisfactory separations have been obtained for the nickel porphyrinic species.Although the occurrence of precipitation of the extracts hinders the distinct speciation of metalloporphyrins with reversed phase chromatography, the precipitation/dissolution phenomena showed some interesting features as a clean-up step for diluted crude oil samples and oil fractions. 相似文献
52.
Two phase immiscible flow in petroleum reservoirs is considered. Various formulations of the governing equations that describe this flow, including phase, global, and weighted formulations, are numerically experimented. Mixed finite element methods are used to solve these formulations. Our experiments show that the numerical results obtained using the phase and global formulations match well in terms of production rates, characterization curves, and water cuts. 相似文献
53.
Large quantity of aged petroleum oil contamination such as dehydrated oil sludge, generated in the disposal process of oil-containing sewage in Indonesia. This study aims to investigate the OSCS removal by mean of bioremediation technique. Results found that petrofilic consortia and biosurfactants addition increased the removal efficiency up to 46% and 85%, respectively. At full scale application, this technique succeed in removing of 46 g TPH per kg soil from 4 883 m3 of OSCS during 16 mo of treatment. These results suggest that petrofilic consortia and biosurfactants addition stimulate the biodegradation and overcome the limitation of OSCS degradation process. 相似文献
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Mores D Kornatowski J Olsbye U Weckhuysen BM 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(10):2874-2884
Coke formation during the methanol‐to‐olefin (MTO) conversion has been studied at the single‐particle level with in situ UV/Vis and confocal fluorescence microscopy. For this purpose, large H‐ZSM‐5 crystals differing in their Si/Al molar ratio have been investigated. During MTO, performed at 623 and 773 K, three major UV/Vis bands assigned to different carbonaceous deposits and their precursors are observed. The absorption at 420 nm, assigned to methyl‐substituted aromatic compounds, initiates the buildup of the optically active coke species. With time‐on‐stream, these carbonaceous compounds expand in size, resulting in the gradual development of a second absorption band at around 500 nm. An additional broad absorption band in the 600 nm region indicates the enhanced formation of extended carbonaceous compounds that form as the reaction temperature is raised. Overall, the rate of coke formation decreases with decreasing aluminum content. Analysis of the reaction kinetics indicates that an increased Brønsted acid site density facilitates the formation of larger coke species and enhances their formation rate. The use of multiple excitation wavelengths in confocal fluorescence microscopy enables the localization of coke compounds with different molecular dimensions in an individual H‐ZSM‐5 crystal. It demonstrates that small coke species evenly spread throughout the entire H‐ZSM‐5 crystal, whereas extended coke deposits primarily form near the crystal edges and surfaces. Polarization‐dependent UV/Vis spectroscopy measurements illustrate that extended coke species are predominantly formed in the straight channels of H‐ZSM‐5. In addition, at higher temperatures, fast deactivation leads to the formation of large aromatic compounds within channel intersections and at the external zeolite surface, where the lack of spatial restrictions allows the formation of graphite‐like coke. 相似文献
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Abstract The assignment of a band near 1600 cm?1 in IR spectra of carbons has been controversial for four decades. However, many different carbons have been studied: effectively, a single band assignment was sought for an absorption appearing with three different classes of carbon. As these differ in over-all structure, not one but three explanations are needed. These are discussed. However, undue emphasis has been placed on a single absorption; attention should also be paid to other absorptions accompanying the 1600 cm?1 band. 相似文献
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Fevzi CiǦeroǦxlu 《Isotopes in environmental and health studies》2013,49(10):494-496
The analysis of some elements in fuel oil was done by using neutron capture gamma ray spectroscopy. The gamma rays emitted after the reaction of (n, γ) from the fuel oil atoms bombarded with the thermal neutrons emitted from a 252Cf source were investigated in the energy interval 0 … 10 MeV. The impurity elements in the sample were determined. 相似文献