全文获取类型
收费全文 | 345篇 |
免费 | 9篇 |
国内免费 | 5篇 |
专业分类
安全科学 | 6篇 |
废物处理 | 13篇 |
环保管理 | 42篇 |
综合类 | 38篇 |
基础理论 | 72篇 |
环境理论 | 1篇 |
污染及防治 | 123篇 |
评价与监测 | 44篇 |
社会与环境 | 19篇 |
灾害及防治 | 1篇 |
出版年
2023年 | 4篇 |
2022年 | 7篇 |
2021年 | 16篇 |
2020年 | 4篇 |
2019年 | 7篇 |
2018年 | 9篇 |
2017年 | 18篇 |
2016年 | 15篇 |
2015年 | 9篇 |
2014年 | 15篇 |
2013年 | 42篇 |
2012年 | 13篇 |
2011年 | 37篇 |
2010年 | 21篇 |
2009年 | 20篇 |
2008年 | 24篇 |
2007年 | 21篇 |
2006年 | 12篇 |
2005年 | 17篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 10篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 6篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1989年 | 4篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有359条查询结果,搜索用时 15 毫秒
71.
72.
Dust emission calculations in open storage piles protected by means of barriers, CFD and experimental tests 总被引:1,自引:0,他引:1
Javier Toraño Susana Torno Isidro Diego Mario Menendez Malcolm Gent 《Environmental Fluid Mechanics》2009,9(5):493-507
The importance of open mineral storage piles in bulk solids port terminals have increased considerably in recent years in Europe and USA (in Spain, great extensions of transoceanic ports are being made) to address the increasing demand of raw material importation due to local mining operation closure. These storage piles are affected by the climatologically processes and the dust emission to the atmosphere, causing repercussions to health and environmental, which is intimately related to the air velocity, according to USEPA studies, maximum ratio of dust emission emitted from CFD and software Ansys CFX 10.0 is determined. In addition, an emission variability study based on the pile distance of different height solid barriers is developed, reducing the emission to 66%. The studies have been contrasted by published investigations and industrial measurement. 相似文献
73.
The modern sociological literature on disasters highlights the fact that many of the ideas about human behaviour in disasters which were long considered as valid, are wrong. The main discovery is based on the fact that situations of crisis increase people's moral principles and capability of response. This paper illustrates some of these ideas, in a case study of a village which was struck by a natural disaster in the north of Granada (Spain) in 1986. The population's attitude revealed a huge potential of resources that were underestimated by professionals of disaster management. The analysis shows that it is necessary to bring civil protection systems and the population's capability of response into close harmony. 相似文献
74.
The organic fraction of a municipal solid waste was added in different doses to an eroded soil formed of loam and with no
vegetal cover. After three years, the changes in macronutrient content and the chemical-structural composition of its organic
matter were studied. The addition of the organic fraction from a municipal solid waste had a positive effect on soil regeneration,
the treated soils being covered with spontaneous vegetation from 1 yr onwards. An increase in electrical conductivity and
a fall in pH were noted in the treated soils as were increases in macronutrients, particularly N and available P and the different
carbon fractions. Optical density measurements of the organic matter extracted with sodium pyrophosphate showed that the treated
soils contained an organic matter with less condensed compounds and with a greater tendency to evolve than the control. A
pyrolysis-gas chromatography study of the organic matter extracted with pyrophosphate showed large quantities of benzene both
in the treated soils and control; pyrrole was also relatively abundant, although this fragment decreased as the dose rose.
Xylenes and pyridine were present in greater quantities in the control and furfural in the treated soils. Three years after
addition to the soil, the organic matter had a higher proportion of fragments derived from aromatic compounds and a smaller
proportion derived from hydrocarbons. Similarity indices showed that, although the added and newly formed organic matter 3
yr after addition continued to differ from that of the original soil and to be more mineralizable, the transformations it
has undergone made it more similar to the original organic matter of the soil than it was at the moment of being added. 相似文献
75.
New-production (nitrate uptake) rates in the equatorial Pacific were estimated by parallel measurements of nitrate disappearance
from sea water using a colorimetric method and of 15N-labelled nitrate (15NO3
−) incorporation into particulate organic nitrogen (PON) collected on GF/F filters (net nitrate uptake, conventional 15N-tracer method) and Anopore (0.2 μm) membranes. Regression analyses of 74 sample pairs gathered during 12 and 24 h productivity
experiments revealed a significant positive relationship between decreasing nitrate level and 15NO3
− accumulation into PON retained on GF/F filters, but the slopes of Model I and Model II regression lines were 1.18 and 1.29,
respectively, suggesting that 15 to 22% of 15NO3
− removed from the dissolved fraction were lost to another N-pool. Two possible avenues for the missing 15NO3
− have been examined: uptake by submicron particles passed through the GF/F filters, and loss as dissolved organic nitrogen
(DON). Nitrate uptake by small cells not recovered on GF/F filters, could be safely eliminated as a cause of loss, since 15NO3
− uptake rates obtained from 15N entering PON collected on GF/F filters agreed well with those obtained from 15N entering PON collected on Anopore membranes (32 sample pairs). Inspection of the DON pool of 0.2 μm filtrates for excess-15N enrichment (20 samples) revealed that in nitrate-rich waters (equatorial upwelling between 1°N and 10°S), loss of 15NO3
− as DO15N accounted for <5% of net nitrate uptake. In samples from subtropical oligotrophic waters (from 11°S southward), however,
15NO3 loss as DO15N represented up to 20% of net NO3
− uptake. These results, as well as experimental considerations concerning the use of colorimetric and isotopic methods to
measure new production show that: (1) earlier reported high discrepancies between nitrate decreases (ΔNO3
−) and 15NO3
− incorporation into filterable particles (ΔNO3
−/15NO3
− incorporation >2) were probably erroneous; (2) the use of GF/F filters does not result in an underestimation of new production,
although it was found to underestimate PON concentrations by up to 60%; (3) in the equatorial upwelling area (1°N to 10°S),
which has high ambient nitrate levels (>2000 nmol l−1) but only slight changes in concentration (0 to 80 nmol l−1 d−1), new production is more accurately estimated by the isotopic method than by the chemical method; (4) in subtropical oligotrophic
waters (from 11°S southward) with low ambient nitrate levels (0 to 100 nmol l−1), both procedures are appropriate as long as nitrate removal per incubation period is >3 nmol l−1 (lower rates are only detectable with the isotopic method); (5) the traditional 15N-tracer technique does not substantially underestimate net new-production in the equatorial Pacific, and failure to account
for the loss of 15NO3
− as DON, i.e. to estimate gross nitrate uptake (gross uptake = net uptake + 15N loss) tends to underestimate new production on an average by only 10%. Overall, the apparent low level of new production
in the nitrate-rich area of the central equatorial Pacific seems to be a fact, and may be ascribable to other nutrient (macro
and micro) deficiencies and/or to intense in situ recycling of ammonium and nitrate (regenerated production) rather than to
inaccurate nitrate uptake rates measured with the classical 15N-tracer technique.
Received: 24 November 1998 / Accepted 10 March 2000 相似文献
76.
Mendoza A Garcia MR Vela P Lozano DF Allen D 《Journal of the Air & Waste Management Association (1995)》2005,55(12):1797-1808
An inventory of air pollutants emitted from forest and agricultural fires in Northeastern Mexico for the period of January to August of 2000 is presented. The emissions estimates were calculated using an emissions factor methodology. The inventory accounts for the emission of carbon monoxide (CO), methane, nonmethane hydrocarbons, ammonia, nitrogen oxides, and particulate matter (PM). Particulate matter emissions include estimates for fine PM and coarse PM. A total of 2479 wildfires were identified in the domain for the period of interest, which represented approximately 810,000 acres burned and 621,130 short tons emitted (81% being CO). The main source of information used to locate and estimate the extent of the fires came from satellite imagery. A geographic information system was used to determine the type of vegetation burned by each fire. More than 54% of the total area burned during the period of study was land on the State of Tamaulipas. However, >58% of the estimated emissions came from the State of Coahuila. This was because of the mix of vegetation types burned in each state. With respect to the temporal distribution, 76.9% of the fires occurred during the months of April and May consuming almost 78% of the total area burned during the period of study. Analysis of wind forward trajectories of air masses passing through the burned areas and 850-mb wind reanalyses indicate possible transboundary transport of the emissions from Mexico to the United States during the occurrence of the major wildfires identified. 相似文献
77.
Evaluation of heavy metal availability in polluted soils by two sequential extraction procedures using factor analysis 总被引:34,自引:0,他引:34
Maiz I Arambarri I Garcia R Millán E 《Environmental pollution (Barking, Essex : 1987)》2000,110(1):3-9
Superficial soil and grass samples from 13 locations affected by several anthropogenic sources (mining, metal factory, traffic emissions) were collected in Gipuzkoa, northern Spain. The more labile metal fractions, the mobile (extracted by 0.01 mol l(-1) CaCl(2)) and the mobilisable (extracted by 0.005 mol l(-1) DTPA), were evaluated using a short sequential procedure with two steps. From the results a short-medium term potential lability of Cd, Cu, Zn and Pb can be concluded. The labile levels were compared with the results obtained using the Tessier sequential procedure. Factor analysis was used to check the associations between the total metal contents in soil and grass, as well as between the levels of the different sequential fractions and the total content in grass. Cd, Cu and Zn labile levels were related to total metal grass contents indicating its suitability for the availability studies in polluted soil-plant system. 相似文献
78.
Structure-activity relationships for association of linear alkylbenzene sulfonates with activated sludge 总被引:4,自引:0,他引:4
Sorption of linear alkylbenzene sulfonates (LAS) on sludge particles from wastewater treatment plants was studied. The effect of alkyl chain length and the water hardness were investigated. Sorption on sludge increases with increasing alkyl chain length in the LAS molecules. The results are interpreted in terms of a hydrophobic bonding mechanism being the critical micelle concentration a good index of the surfactant hydrophobicity. The increase in free energy of adsorption for the addition of successive methylene groups to the alkyl chain was estimated as 2.4 kJ/mol. Water hardness clearly enhances the sorption of LAS homologues on sludge and seems to promote cooperative sorption at high surfactant and calcium ion concentrations. An empirical equation was provided that allow to estimate the partition coefficient between aqueous and solid phases for LAS homologues as a function of the alkyl chain length and the water hardness. 相似文献
79.
Extinction-Rate Estimates for a Modern Neotropical Flora 总被引:1,自引:0,他引:1
80.
Alejandra Valero Robyn Hudson Edgar Ávila Luna Constantino Macías Garcia 《Behavioral ecology and sociobiology》2005,59(2):262-269
When approached by males, females of the Amarillo fish (Girardinichthys multiradiatus) perform a behaviour called vibration or they are aggressively challenged. We quantified vibration and assessed whether it compromises the rate of feeding attempts in dyads kept in outdoor enclosures. Male approaches resulted in female vibration and in a reduced feeding rate. Vibration was not evoked by female–female aggression, which was frequent and always ended in the subordinate fleeing from the dominant female. Using a closed respirometer we found that vibration is costly; oxygen consumption of females was greater in the presence of a male (which evoked vibration) than in the presence of a non-familiar female (when no vibration occurred). By recording interactions of females confined in aquaria in the presence and in the absence of males, we confirmed that escaping is the only available response to deal with female aggression. Females kept without males participated in frequent aggressive (even lethal) interactions that did not abate while the subordinate female was in sight of the dominant, and which caused premature births and injuries. Yet in the alternative treatment aggression ceased when a male approached, prompting vibration in both females. Thus, in the Amarillo, in as much as it evokes energetically costly female vibrations, male courtship is an expression of sexual conflict. However, in the absence of males, frequent female aggression potentially annuls the benefits of not vibrating. We propose that a complete appraisal of the consequences of sexual conflict must include an assessment of the costs imposed by intra-sexual interactions. 相似文献