全文获取类型
收费全文 | 109篇 |
免费 | 2篇 |
专业分类
安全科学 | 2篇 |
废物处理 | 9篇 |
环保管理 | 14篇 |
综合类 | 12篇 |
基础理论 | 13篇 |
环境理论 | 1篇 |
污染及防治 | 40篇 |
评价与监测 | 12篇 |
社会与环境 | 8篇 |
出版年
2023年 | 1篇 |
2022年 | 5篇 |
2021年 | 7篇 |
2020年 | 4篇 |
2019年 | 2篇 |
2018年 | 6篇 |
2017年 | 6篇 |
2016年 | 7篇 |
2015年 | 3篇 |
2014年 | 12篇 |
2013年 | 9篇 |
2012年 | 2篇 |
2011年 | 5篇 |
2010年 | 5篇 |
2009年 | 10篇 |
2008年 | 3篇 |
2007年 | 4篇 |
2006年 | 1篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1993年 | 1篇 |
1990年 | 1篇 |
1984年 | 1篇 |
1980年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有111条查询结果,搜索用时 515 毫秒
61.
Samira Veiga Ravaiano Wagner Faria Barbosa Lúcio Antônio Campos Gustavo Ferreira Martins 《Die Naturwissenschaften》2018,105(7-8):48
The insect immune system faces various challenges; particularly in social bees, caste system and age polyethism expose individuals to numerous environmental and working conditions. However, little is known about how cellular defenses in social bees may be organized to respond to a variety of immune challenges. Here, we describe the morphological features and the total and differential counts of hemocytes in different female classes (newly emerged workers, nurses, foragers, and virgin queens) of the eusocial stingless bee Melipona quadrifasciata. Granulocytes and prohemocytes were, respectively, the most and the least abundant cells among all classes of females. Furthermore, there were more prohemocytes in virgin queens than in foragers. The total number of hemocytes was smaller in foragers, whereas the largest number was observed in nurse workers. This reduced amount of hemocytes in foragers might allow energy savings to perform colony activities such as foraging and defense. Foragers also had the biggest hemocytes (either prohemocytes, granulocytes, or plasmatocytes) in comparison to the other classes of females, which might have arisen as a compensation for the reduction in number of these cells during aging. These results suggest that profiles of hemocytes of M. quadrifasciata vary according to the caste and age of this eusocial bee. 相似文献
62.
Infestation by leeches on adult freshwater turtles Phrynops geoffroanus in two areas of the Uberabinha River, in Uberlandia, was investigated during the summer (January 2000). Fifty eight turtles were trapped: 26 (12 males, 14 females) in an agricultural area and 32 (16 males, 16 females) in an area with a more urban environment. The females present larger length and body mass (291.77+/-29.18 mm; 2233.30+/-511.40 g) than males (259.71+/-33.15 mm; 1488.68+/-529.35 g). Blood samples were drawn from the retrorbital sinus using heparinized micro-hematocrit capillary tubes, for microscopic and direct examination for intracellular parasites. Ectoparasitism by leeches, Placobdella bistriata, on young and adult animals was observed in the limb cavities of 28.1% of the urban area turtles. No leeches were found on the turtles in the agricultural area. Hemogregarine erythrocytic gametocytes were found in 15.4% of the agricultural area turtles, and in 37.5% of the urban area turtles. Concurrent parasitism by leeches and hemogregarines on the same individuals was seen on six turtles. Infections with microorganisms (bacteria and fungus) facilitated by the bites of leeches were not observed in another study on the same sample of infested turtles. However, 19% of the turtles collected in the agricultural area and 15% of the turtles from the urban area presented normocytic acute anemia. The occupation of the soil apparently interfered in the aquatic ecosystem favoring parasitism in the urban area. 相似文献
63.
Effect of the alkyl chain length on the anaerobic biodegradability and toxicity of quaternary ammonium based surfactants 总被引:2,自引:0,他引:2
The anaerobic biodegradability and toxicity to methanogenic gas production of different alkyl chain length homologs of quaternary ammonium based surfactants were examinated. Two series of these cationic surfactants were selected: alkyl trimethyl ammonium and alkyl benzyl dimethyl ammonium compounds. A simple anaerobic gas production test containing municipal digester solids as a source of anaerobic bacteria was used. Under the applied methanogenic conditions, the cationic surfactants tested showed a very poor primary biodegradation and no evidence of any extent of ultimate biodegradation was observed. The toxicity of quaternary ammonium based surfactants to methanogenic gas production decreased with increasing the alkyl chain length. 相似文献
64.
Paulina Concha Larrauri Juan Pablo Campos Gutierrez Upmanu Lall Mounir Ennenbach 《Journal of the American Water Resources Association》2020,56(2):247-269
We assess the potential financial benefits of rooftop rainwater harvesting (RWH) in Mexico City from the perspective of property owners and entrepreneurs. A bottom‐up approach was followed by evaluating RWH at individual buildings and aggregating the results to a borough/city level. We consider sector‐specific water demands, potable and nonpotable uses, and user‐specific water tariffs. We find that RWH is economically most beneficial for nondomestic users rather than for small domestic users, who are often the target of RWH interventions. Based on a net present value analysis, a potable RWH system is not favored for most domestic users under the current subsidized municipal water tariff structure. Our analysis only considers capital and maintenance expenses, and not other benefits related to increased access to water and reliability, or social benefits from a switch to a RWH system. If the initial capital expense for RWH is partly financed by transferring the water subsidy to an entrepreneur, then RWH becomes financially attractive for a wide range of domestic users. To improve water access in Mexico City, RWH is attractive in the most marginalized boroughs where water use is currently lower and precipitation is higher. For domestic users relying on trucked water, RWH can have great financial benefits. Our approach provides quantitative data with high spatial specificity, highlighting the places and types of users that would benefit most from RWH. 相似文献
65.
Clístenes Williams Araújo do Nascimento Luiz Henrique Vieira Lima Franklone Lima da Silva Caroline Miranda Biondi Milton César Costa Campos 《Environmental monitoring and assessment》2018,190(10):606
The soils of the Brazilian Amazon exhibit large geochemical diversity reflecting the different soil formation processes in an area covering 49% of the Brazilian territory. Soil contamination by heavy metals is one of the threats to the sustainability of this Biome but establishing quality reference values (QRVs) for the region is a challenging owing to the immense territorial area of the Amazon. This study aimed to determine the natural background of heavy metals in soils from the southwestern Brazilian Amazon in order to propose QRVs for Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sb, and Zn for alluvial sedimentary soils. One hundred and twenty-eight soil samples were collected at a depth of 0.0–0.2 m in sites with minimal anthropogenic interference. Soil sample digestion was based on the EPA 3051A method and metal concentrations were determined by ICP-OES. QRVs calculated for the southwestern Brazilian Amazon are among the lowest recorded in Brazil (mg kg?1): Ba (16.5), Cd (0.1), Cr (6.9), Cu (2.8), Fe (15.4), Mn (13.4), Ni (1.7), Pb (4.4), Sb (0.9), and Zn (5.7). The low metal concentration is likely a result of the sedimentary origin of the soils. The results of this study can serve as a basis for defining public policies to investigate the environmental impacts resulting from changes in land use in areas of the Brazilian Amazon. 相似文献
66.
Cosate de Andrade Marina Fernandes Loureiro Hugo Campos Sarantopóulos Claire Isabel Grígoli de Luca Morales Ana Rita 《Journal of Polymers and the Environment》2021,29(10):3288-3301
Journal of Polymers and the Environment - This work assesses the influence of the plasticizer polyethylene glycol (PEG) on the compatibilization of poly (butylene adipate-co-terephthalate) (PBAT)... 相似文献
67.
Land-users’ perceptions and adaptations to climate change in Mexico and Spain: commonalities across cultural and geographical contexts 总被引:1,自引:0,他引:1
Minerva Campos Michael K. McCall Marc González-Puente 《Regional Environmental Change》2014,14(2):811-823
Comparing agricultural management practices across scales and in different cultural settings can reveal shared insights into the capacity to adjust and respond to change and uncertainty. Differences make comparisons in environmental risk perceptions and responses particularly interesting and valuable, with obtained similarities being in many ways more interesting than found differences, which might be readily expected in places with remarkable geographical and demographic differences. People’s perception of climatic risks and hazards appears to be important to understand the context in which adaptation strategies to climate change emerge. Our intention, rather than compare the two case studies at the local scale, one in Mexico and one in Spain, is to identify existing common mechanisms to perceive climate change and to address adaptation among two very different geographical and cultural contexts. The study aims first to explore people’s perceptions of climate change and its outcomes; second to analyse the adaptation measures that they have developed and develop some preliminary ideas about their strategies; and third to consider the capacity of people to cope and adapt endogenously, in terms of the measures that people think that their governments should take to enhance/strengthen them at the local scale. 相似文献
68.
Cassia Roberta Campos Vanessa Alvarenga Mesquita Cristina Ferreira Silva Rosane Freitas Schwan 《Waste management (New York, N.Y.)》2014,34(11):2036-2046
Molasses-based distilleries are one of the most polluting industries generating large volumes of high strength wastewater called vinasse. Different processes covering anaerobic, aerobic as well as physicochemical methods have been employed to treat this effluent. This study evaluated the microbial communities present in the vinasse during different stages of its treatment by traditional and molecular methods. The analysis of the efficiency of each treatment was performed by physicochemical parameters and toxicity analysis. The treatment of vinasse was performed in the following steps: high flow fermentation; filtration; chemical flakes; low-flow fermentation; filtration; and neutralization. The physicochemical analysis in different stages of the vinasse treatment demonstrated that phases of treatment influenced the performance of the evaluated parameters. Among the 37 parameters, 9 were within the limits established by the Commission for Environmental Policy of Minas Gerais, Brazil (COPAM), especially BOD (96.7% of pollution reduction), suspended solids (99.9%), pH, copper (88%), iron (92.9%), and manganese (88%). Some parameters, even after treatment, did not fit the maximum allowed by legislation. The microbial population decreased reaching 3 log CFU/ml present in the steps of the flakes chemical and disinfection treatment of vinasse. Lactobacillus brevis and Pichia kudriavzevii were present in all stages of the treatments, showing that these microorganisms were resistant and demonstrated that they might be important in the treatment of vinasse. The vinasse showed a significant reduction of pollution load after the disinfection treatment however still should not be discarded into water bodies because the high values of tannins and sediment solids, but suggest the use of the effluent in the cooling coil during the distillation process of the beverage. 相似文献
69.
R. R. Miranda A. L. R. Damaso da Silveira I. P. de Jesus S. R. Grötzner C. L. Voigt S. X. Campos J. R. E. Garcia M. A. F. Randi C. A. Oliveira Ribeiro F. Filipak Neto 《Environmental science and pollution research international》2016,23(6):5179-5188
The impact of nanoparticles on fish health is still a matter of debate, since nanotechnology is quite recent. In this study, freshwater benthonic juvenile fish Prochilodus lineatus were exposed through water to three concentrations of TiO2 (0.1, 1, and 10 μg l?1) and ZnO (7, 70, and 700 μg l?1) nanoparticles, as well as to a mixture of both (TiO2 1 μg l?1?+?ZnO 70 μg l?1) for 5 and 30 days. Nanoparticle characterization revealed an increase of aggregate size in the function of concentration, but suspensions were generally stable. Fish mortality was high at subchronic exposure to 70 and 700 μg l?1 of ZnO. Nanoparticle exposure led to decreased acetylcholinesterase activity either in the muscle or in the brain, depending on particle composition (muscle—TiO2 10 μg l?1; brain—ZnO 7 and 700 μg l?1), and protein oxidative damage increased in the brain (ZnO 70 μg l?1) and gills (ZnO 70 μg l?1 and mixture) but not in the liver. Exposed fish had more frequent alterations in the liver (necrosis, vascular congestion, leukocyte infiltration, and basophilic foci) and gills (hyperplasia and epithelial damages, e.g., epithelial disorganization and epithelial loss) than the control fish. Thus, predicted concentrations of TiO2 and ZnO nanoparticles caused detectable effects on P. lineatus that may have important consequences to fish health. But, these effects are much more subtle than those usually reported in the scientific literature for high concentrations or doses of metal nanoparticles. 相似文献
70.
Current accelerating biodiversity loss is by many conservationists regarded as a result of economic development. Some economists agree on this viewpoint but argue it is valid at low income levels because of the need to secure a minimum living standard. On the other hand, economic development at higher income levels can instead mitigate biodiversity loss because of improved willingness and affordability to implement measures such as protected areas. This so-called environmental Kuznets relation is tested in this study by econometric analysis of cross-sectional data on a global scale. However, the results do not support this relation. Instead, we found a relation between economic and institutional development where economic development decreases biodiversity loss at a minimum level of institutional quality, i.e. minimum capacity to implement and secure property rights for the citizens. Our results thus question policies that neglect institutional quality for reversing biodiversity loss. Further, it was found that biodiversity loss increases with invasive species, high average temperature and precipitation, and spatial autocorrelation. 相似文献