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1.
武汉市区第四系含水层地下水有机污染敏感性研究 总被引:14,自引:0,他引:14
在详细调查武汉市水文地质条件和地下水污染现状的基础上,获得了高精度的武汉市水环境中微量有机污染物的组成数据。所检测出的有机组分达30余种,以苯及相关苯系物为主,污染程度较高的地下水主要分布在人口密集区和工业,商业区,应用改进的DRASTIC模型-地下水污染敏感性评价模型,在GIS平台上,编制了武汉市区地下水污染敏感性分区图。根据其评价结果,建议集中对那些敏感性相对较高的区域采取有效的环保措施,开发利用时应作出风险评价。 相似文献
2.
South-western Greenland constitutes an internationally important wintering area for many seabird species. Several species of management concern have a predominantly near-coastal distribution, though available information about seabird numbers is mostly confined to offshore waters. Here we report on extensive aerial surveys conducted in March 1999, covering the coastal waters (up to 15-20 km from the mainland coast) and fjords of south-west Greenland. The most widespread and numerous species were estimated as 463 000 common eiders ( Somateria mollissima ), 153000 king eiders ( S. spectabilis ), 125000 thick-billed murres ( Uria lomvia ), 94 000 long-tailed ducks ( Clangula hyemails ), and 12 000 black guillemots ( Cepphus grylle ). A total of 19 bird species were recorded. The estimates for common eider and long-tailed duck approximately represent the entire winter population in south-western Greenland while estimates for the other species represent only an unknown proportion since their distribution continues further offshore. Waters around Nuuk and within the Julianehåbsbugten (Julianehåb Bay) area were identified as areas of high seabird density. A large proportion of the common eider population was aggregated in the fjord systems (22%), calling attention to the importance of fjords for this species. In contrast, pelagic seabird species appear to be absent from the fjords. The large winter population of common eider reveals the importance of south-western Greenland as a key wintering area for the eastern Canadian breeding population. The western Greenland breeding population is the only other contributor, probably amounting to no more than 15 000 pairs. 相似文献
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Rip currents as a geological tool 总被引:2,自引:0,他引:2
MICHA GRUSZCZYSKI§ STANISAW RUDOWSKI† JULIA SEMIL‡ JAN SOMISKI† JERZY ZROBEK‡ 《Sedimentology》1993,40(2):217-236
This paper considers the nature and sedimentary significance of rip currents. Rip currents are the main factor responsible for the transport of coarse sediments from the littoral zone to greater depths. Such sediments, deposited outside the zone of wave deformation, may be identified as storm rip current increments within sediments deposited during fair weather. Composite beds deposited during a given wave cycle by storm rip currents are closely similar to ‘turbidites’ and many so called ‘fluxo-turbidites’ described from flysch deposits. Using data gathered in studies conducted on the modern Baltic coast, supplemented by experimental work and theoretical considerations, a sedimentary model is proposed. The model may be used to interpret possible rip current deposits among shallow water ‘turbidites’, and both modern storm sediments and ancient ‘tempestites’. 相似文献
7.
Vulnerability of groundwater in Quaternary aquifers to organic contaminants: a case study in Wuhan City,China 总被引:5,自引:0,他引:5
Yanxin Wang Broder J. Merkel Yilian Li Hui Ye Surong Fu Dana Ihm 《Environmental Geology》2007,53(3):479-484
More than 30 organic contaminants were detected in shallow groundwaters at Wuhan, the largest city in central China. Seriously
contaminated groundwaters were from densely populated, industrial and commercial areas. Abnormal concentrations were found
in groundwater from Hankou, downtown Wuhan: trimethylbenzene up to 29 μg/L, tetramethylbenzene up to 866 μg/L, and trichloroethene
up to 9.5 μg/L. Benzene, Toluene, Ethylene and Xylene (BTEX) contamination of groundwater is serious and widespread at Wuhan,
ranging between 0.14 and 25.0 μg/L. Considering the hydrogeological conditions of most Chinese cities, DRAMIC, a modified
version of the widely used DRASTIC model, was proposed by the authors for assessing vulnerability of groundwater to contamination.
The factors D, R, A and I in DRAMIC model are the same as in DRASTIC. The factor topography is ignored. The factor soil media is substituted by a new factor aquifer thickness (M) and the factor hydraulic conductivity of the aquifer by a new factor impact of contaminant (C). The equation for determining the DRAMIC Index is: DRAMIC = 5D
R + 3R
R + 4A
R + 2M
R + 5I
R + 1C
R. The calculated DRAMIC Index can be used to identify areas that are more likely to be susceptible to groundwater contamination
relative to each other. The higher the DRAMIC Index is, the greater the groundwater pollution potential. Applying DRAMIC,
a GIS-based vulnerability map for Wuhan city was prepared. Interestingly, places such as downtown Hankou, where enhanced concentrations
of BTEX have been detected, correspond quite well with those with higher DRAMIC ratings. 相似文献
8.
Past and future polar amplification of climate change: climate model intercomparisons and ice-core constraints 总被引:1,自引:0,他引:1
V. Masson-Delmotte M. Kageyama P. Braconnot S. Charbit G. Krinner C. Ritz E. Guilyardi J. Jouzel A. Abe-Ouchi M. Crucifix R. M. Gladstone C. D. Hewitt A. Kitoh A. N. LeGrande O. Marti U. Merkel T. Motoi R. Ohgaito B. Otto-Bliesner W. R. Peltier I. Ross P. J. Valdes G. Vettoretti S. L. Weber F. Wolk Y. Yu 《Climate Dynamics》2006,27(4):437-440
9.
Assessment of groundwater vulnerability to pollution in Dire Dawa,Ethiopia using DRASTIC 总被引:1,自引:0,他引:1
Assessment of groundwater vulnerability to pollution is an effective tool for the delineation of groundwater protection zones.
DRASTIC approach was used to determine vulnerability zones in Dire Dawa groundwater basin, a semiarid region of Ethiopia.
Maps of the seven DRASTIC parameters were prepared. GIS-ArcView was used for mapping and performing weighted-overlay analysis.
The result of the analysis indicated that eastern part of the study area, in which Dire Dawa town is located, is highly vulnerable.
A low aquifer vulnerability class was determined for the western portion of the study area as a result of greater groundwater
depths, higher relative soil-clay content, and relatively low recharge rates for this area. The area between the two zones
is of medium vulnerability. Observed nitrate concentrations in boreholes are in accordance with the vulnerability map. Some
of the boreholes in the Sabian well field (Dire Dawa area) already deliver groundwater with nitrate levels significantly exceeding
health standards set by the World Health Organization, while boreholes in the western part (low vulnerability zone) contain
almost no nitrate. The result of this study is useful for risk assessments and for the development of effective groundwater
management strategies for this region and others like it. 相似文献
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