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21.
Insolubilized humic acid (IHA) was prepared in the laboratory by heating approach. Through the comparison between the endothermic
peaks, optimal heating temperature was determined to be 330°C. The modified IHA then was characterized by TG-DTA, SEM, FTIR,
element analysis, and nitrogen adsorption–desorption isotherms. The removal efficiency of p-nitrophenol from the aqueous solution by adsorption onto solid IHA surfaces was shown to be a function of pH, reaction temperature,
and p-nitrophenol concentration. Adsorption equilibrium data satisfactorily fitted the Langmuir adsorption isotherm. Under a certain
concentration range, the removal rate of p-nitrophenol at pH 3.5 could reach 24, 29, and 35 mg/g at a temperature of 25, 35, and 45±0.1°C. The results suggest that
IHA could play a role as a potential efficient absorbent to remove organic contaminants, e.g., utilized to purify water contaminated
by organic compounds. 相似文献
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This paper presents results obtained from a series of experiments conducted in wave flume to assess the influence of the offshore low-crested breakwater as a defence structure in reducing the wave forces on vertical seawall. The main aim of the tests was to know the effect of crest elevation of the offshore low-crested breakwater as a rehabilitation structure for the existing damaged shore protection structures. In this study five relative breakwater heights are used and associated flow evolution was analyzed. With the sections proposed in this study, it is possible to achieve considerable reduction of wave force on the seawall. Modification factor is proposed to estimate the shoreward force on the seawall defenced by low-crested breakwater. 相似文献
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Nam H. Tran 《Computational Geosciences》2007,11(3):249-260
Simulated annealing (SA) has the capacity to handle complex problem of fracture heterogeneity. However, its applications to
characterization and modeling of an actual discrete fracture network are limited. Borrowing the context of geothermal reservoirs
(where extensive discrete fractures exist), this paper attempts to solve several key practical issues that persist in current
models: objective function’s (OF’s) formulation, modification scheme, and stop criteria. The improvements are examined in
a case study on an actual fracture outcrop, where results are compared with a current and advanced SA work. 相似文献
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Tatyana I. Moiseenko Andrey N. Sharov Lubov P. Kudryavtseva Catherine Rose 《Limnologica》2009,39(1):1-13
In this study, published data on Lake Imandra, north-west Russia, have been synthesised to investigate trends in lake contamination and recovery due to changing inputs of heavy metals and nutrients over time. Records of water chemistry, phytoplankton, zooplankton and fish communities have been used to determine the status of aquatic ecosystem health in three distinct phases of Lake Imandra's recent history. Firstly, background (reference) conditions within the lake have been established to determine lake conditions prior to anthropogenic influences. Secondly, a period of ecosystem degradation due to anthropogenic inputs of toxic metals and nutrients has been described. Finally, evidence of lake recovery due to recent decreases of toxic metals and nutrients has been explored. Pollution of Lake Imandra began in the 1930s, reaching a peak in the 1980s. Increases in heavy metal and nutrient inputs transformed the typical Arctic ecosystem. During the contamination phase, there was a decrease in Arctic species and in biodiversity. During the last 10 years, pollution has decreased and the lake has been recolonised by Arctic water species. Ecosystem recovery is indicated by a change of predominant species, an increase in the individual mass of organisms and an increase in the biodiversity index of plankton communities. In accordance with Odum's ecosystem succession theory, this paper demonstrates that the ecosystem has transformed to a more stable condition with new defining parameters. This illustrates that the recovery of Arctic ecosystems towards pre-industrial reference conditions after a reduction in anthropogenic stresses occur, although a complete return to background conditions may not be achievable. Having determined the status of current ecosystem health within Lake Imandra, the effect of global warming on the recovery process is discussed. Climate warming in Arctic regions is likely to move the ecosystem towards a predominance of eurybiontic species in the community structure. These organisms have the ability to tolerate a wider range of environmental conditions than typical Arctic inhabitants and will gain advantages in development. This indicates that the full recovery of Arctic ecosystems in a warming climate may not be possible. 相似文献
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通过对DPX1型601蒸发器测针报警器进行改造,将原测针和报警器合成一体,用光亮报警替代声音报警,提高了仪器灵敏度,降低故障率,操作更简便,有利于提高蒸发观测数据的准确性. 相似文献