全文获取类型
收费全文 | 489篇 |
免费 | 4篇 |
国内免费 | 6篇 |
专业分类
安全科学 | 19篇 |
废物处理 | 20篇 |
环保管理 | 73篇 |
综合类 | 53篇 |
基础理论 | 105篇 |
污染及防治 | 154篇 |
评价与监测 | 49篇 |
社会与环境 | 24篇 |
灾害及防治 | 2篇 |
出版年
2023年 | 3篇 |
2022年 | 15篇 |
2021年 | 23篇 |
2020年 | 10篇 |
2019年 | 13篇 |
2018年 | 11篇 |
2017年 | 16篇 |
2016年 | 34篇 |
2015年 | 16篇 |
2014年 | 20篇 |
2013年 | 50篇 |
2012年 | 47篇 |
2011年 | 43篇 |
2010年 | 33篇 |
2009年 | 26篇 |
2008年 | 27篇 |
2007年 | 21篇 |
2006年 | 22篇 |
2005年 | 13篇 |
2004年 | 16篇 |
2003年 | 10篇 |
2002年 | 11篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
排序方式: 共有499条查询结果,搜索用时 218 毫秒
261.
Rodríguez-Galán Mónica Baena-Moreno Francisco M. Vázquez Sara Arroyo-Torralvo Fátima Vilches Luis F. Zhang Zhien 《Environmental Chemistry Letters》2019,17(4):1529-1538
Environmental Chemistry Letters - Acid mine drainage induced by the mining industry causes environmental and economic issues. Acid mine drainage contains mainly metals such as Fe, Al, Cu, Ca, Mg,... 相似文献
262.
López FA Centeno TA Alguacil FJ Lobato B López-Delgado A Fermoso J 《Waste management (New York, N.Y.)》2012,32(4):743-752
This work reports the effect of pressure on the steam/oxygen gasification at 1000 °C of the char derived from low temperature-pressure distillation of granulated scrap tyres (GST). The study was based on the analysis of gas production, carbon conversion, cold gas efficiency and the high heating value (HHV) of the product. For comparison, similar analyses were carried out for the gasification of coals with different rank.In spite of the relatively high ash (≈12 wt.%) and sulphur (≈3 wt.%) contents, the char produced in GST distillation can be regarded as a reasonable solid fuel with a calorific value of 34 MJ kg−1. The combustion properties of the char (EA ≈ 50 kJ mol−1), its temperature of self-heating (≈264 °C), ignition temperature (≈459 °C) and burn-out temperature (≈676 °C) were found to be similar to those of a semi-anthracite.It is observed that the yield, H2 and CO contents and HHV of the syngas produced from char gasification increase with pressure. At 0.1 MPa, 4.6 Nm3 kgchar−1 of syngas was produced, containing 28% v/v of H2 and CO and with a HHV around 3.7 MJ Nm−3. At 1.5 MPa, the syngas yield achieved 4.9 Nm3 kgchar−1 with 30% v/v of H2-CO and HHV of 4.1 MJ Nm−3. Carbon conversion significantly increased from 87% at 0.1 MPa to 98% at 1.5 MPa.It is shown that the char derived from distillation of granulated scrap tyres can be further gasified to render a gas of considerable heating value, especially when gasification proceeds at high pressure. 相似文献
263.
This work analyses the separate collection systems used in Spanish towns with between 5000 and 50,000 inhabitants. The study looks at the systems and their efficiency by means of the indicators fractioning rate, quality in container rate and separation rate. The results obtained are compared with those from a similar study conducted earlier that was applied to towns and cities with populations over 50,000. It can be concluded that the most widely implemented system in Spain involves the collection of mixed waste from kerbside bins and picking up paper/cardboard, glass and lightweight packaging from drop-off points. Findings show that the best system is the one that collects mixed waste, organic material and multiproduct waste door-to-door, and glass from drop-off points. The indicator separation rate made it possible to establish beta regression models to analyse the influence of the following logistic variables: inhabitants per point (people/pt), time (years) and frequency of collection (freq). From these models it can be seen that people/pt has a negative effect on all the fractions, while freq and years have a positive effect in the case of paper. 相似文献
264.
We present a simple dynamic model to get some key insights about the substitution of renewable for nonrenewable resources and the consequences for sustainability. We highlight the role of the elasticity of substitution (technological component) to determine the adjustment of production as a response to scarcity and growing ability of resources (environmental component). In some cases, the model predicts a smooth substitution of renewable for nonrenewable resources, but this process could work in the opposite direction if renewable resources are temporarily beyond their maximum sustainable yield, so that their marginal natural growth is negative. If substitution possibilities are high enough, it may be optimal to suspend the extraction of a resource to allow the biomass to regenerate. A production process is more likely to be sustainable the more heavily it depends on renewable, rather than nonrenewable resources. 相似文献
265.
Carlos Garcia Teresa Hernandez Ascension Barahona Francisco Costa 《Environmental management》1996,20(1):133-141
Twenty-one severely eroded soils of SE Spain (Torriorthent xeric soils) were studied. These soils form a fragile system characterized
by soils with a low density of plant cover (<5%), are loamy and occur in a semiarid climate. The soils formerly were used
for agricultural purposes but were abandoned at least 15 years ago. These eroded soils had a low total organic carbon content,
and their humic substances, humic acid carbon, and carbohydrates were lower compared with soils that had never been cultivated
(natural soils). The variables in which the effects of erosion were particularly noted were those related with the active
organic matter (respiration and water-soluble organic matter). Those eroded soils with higher salt content showed lower organic
matter and carbohydrate contents. Only total nitrogen was correlated with the carbon fractions in the eroded soils. 相似文献
266.
Seven mixtures from four organic residues—an aerobic sewage sludge, a city refuse, a peat residue, and a grape debris—were
composted, and the changes undergone by their different carbon fractions during their composting and maturation were studied.
In most cases a decrease in carbon fractions during the composting and maturation processes was observed. The extractable
carbon, however, increased during maturation. Organic matter mineralization was greater in the composts with city refuse than
in those with sewage sludge. The samples with peat residue showed the lowest decreases in carbon fractions. During maturation,
an increase of humiclike fraction was observed, which was reflected by a decrease in the soluble carbon-precipitated carbon
ratio at pH 2. Water-soluble carbon was the carbon fraction most easily degradable by microorganisms, and its amount correlated
significantly with composting time in all the samples. 相似文献
267.
Paulo Petersen José Maria Tardin Francisco Marochi 《Environment, Development and Sustainability》1999,1(3-4):235-252
It is currently estimated that 40 million hectares worldwide are cultivated through no-tillage systems (Derpsh, 1998). Small family farms account for less than 50,000ha, half of them located in South America's Southern Cone (Wall, 1998). Many hypotheses have been offered to explain why so few small farmers have adapted to this method. The most simplistic ones relate this limited adoption to small farmers' traditionalism and to their rejection of innovation. Others point to the low technological development of animal-drawn equipment needed for this technology or the low educational level of family farmers.Results of work done in the Center-South of Paraná, Southern Brazil, by AS-PTA1 in partnership with the region's Forum of Family Farmers Organizations, challenge these hypotheses and draw attention to the need for new approaches and processes of research and extension if the goal is to disseminate and implement appropriate no-tillage systems among family farmers. One requisite is to lower production costs of this method through elimination of herbicides and using green manure and cover crops that shift the crop-weed balance in favor of crops. 相似文献
268.
The biodiversity of many Brazilian rivers is seriously threatened by industrial and municipal pollution, and Rio Paraiba do Sul, located between two major industrial centers is one example of this situation. A survey of the fish assemblage was conducted from October 1998 to September 1999 and the data were used to develop an index of biotic integrity (IBI). We sampled three zones in bracketing a large urban–industrial complex to evaluate water quality changes and the usefulness of the IBI as a monitoring tool. Water quality was classified as poor upstream of the effluent discharges, very poor near the discharges, and poor–fair downstream of the discharges, with this latter situation revealing the current biological capacity of the river. Physical and chemical habitat characteristics were also measured at each site to construct an independent environmental index to validate the IBI. The habitat and IBI indices were highly correlated, suggesting this IBI would be applicable to other large rivers in southeast Brazil. 相似文献
269.
Grais RF Coulombier D Ampuero J Lucas ME Barretto AT Jacquier G Diaz F Balandine S Mahoudeau C Brown V 《Disasters》2006,30(3):364-376
Emergencies resulting in large-scale displacement often lead to populations resettling in areas where basic health services and sanitation are unavailable. To plan relief-related activities quickly, rapid population size estimates are needed. The currently recommended Quadrat method estimates total population by extrapolating the average population size living in square blocks of known area to the total site surface. An alternative approach, the T-Square, provides a population estimate based on analysis of the spatial distribution of housing units taken throughout a site. We field tested both methods and validated the results against a census in Esturro Bairro, Beira, Mozambique. Compared to the census (population: 9,479), the T-Square yielded a better population estimate (9,523) than the Quadrat method (7,681; 95% confidence interval: 6,160-9,201), but was more difficult for field survey teams to implement. Although applicable only to similar sites, several general conclusions can be drawn for emergency planning. 相似文献
270.
Eva Ramírez-Llodra Manuel Ballesteros Joan B. Company Luis Dantart Francisco Sardà 《Marine Biology》2008,153(3):297-309
The spatio-temporal variations in diversity, biomass and abundance of bathyal invertebrates (excluding decapod crustaceans,
which have been analysed elsewhere) from the North-western Mediterranean margin are described. The upper canyon (∼450 m),
middle slope (∼650 m) and lower slope (∼1,200 m) habitats were investigated throughout the year. The first two sites are visited
daily by a specialised commercial fisheries’ fleet, while the deeper site has not been impacted by fishing activities. A total
of 140 species from 12 phyla were collected from the 3 study areas. Of these, the Mollusca, Echinodermata, Polychaeta and
Cnidaria were the most speciose groups. The patterns of species diversity (H′) and evenness (E) were similar in time and space. The upper canyon and middle-slope sites were dominated by echinoderms and molluscs, while
the lower-slope site was dominated by cnidarians and sponges. Multifactorial ANOVA showed significant spatio-temporal differences
in the biomass and/or abundance only in echinoderms, molluscs, cnidarians and polychaetes. The faunal differences observed
were explained by habitat type, but not by season. The role of submarine canyons and commercial fishing on shaping the diversity
and biomass of bathyal Mediterranean invertebrates is discussed.
Luis Dantart: Deceased March 2005 相似文献