首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   260篇
  免费   5篇
  国内免费   1篇
安全科学   7篇
废物处理   24篇
环保管理   26篇
综合类   43篇
基础理论   33篇
污染及防治   81篇
评价与监测   29篇
社会与环境   23篇
  2023年   10篇
  2022年   22篇
  2021年   19篇
  2020年   7篇
  2019年   13篇
  2018年   17篇
  2017年   12篇
  2016年   19篇
  2015年   10篇
  2014年   5篇
  2013年   16篇
  2012年   18篇
  2011年   20篇
  2010年   5篇
  2009年   8篇
  2008年   6篇
  2007年   8篇
  2006年   7篇
  2005年   12篇
  2004年   2篇
  2003年   8篇
  2002年   4篇
  2001年   4篇
  2000年   2篇
  1999年   1篇
  1998年   1篇
  1995年   2篇
  1992年   2篇
  1983年   1篇
  1977年   2篇
  1971年   2篇
  1960年   1篇
排序方式: 共有266条查询结果,搜索用时 46 毫秒
91.
Several physico-chemical properties relevant to determine the environmental impact of ionic liquids - aqueous solubility, octanol/water partition coefficient, chromatographically derived lipophilicity and infinite dilution diffusion coefficients in water - were measured in ionic liquids based on pyridinium, ammonium and pyrrolidinium cations with bis(trifluoromethylsulfonyl)imide anions. The influence of the presence of hydroxyl or ester groups in the physico-chemical properties of these liquids was checked. It appeared that the presence of functional oxygenated moieties reduces the lipophilicity of ionic liquids and so decreases the risk of bioaccumulation in environment.  相似文献   
92.
This paper presents the parameters of municipal solid waste shear strength determined in the laboratory (triaxial tests) and by in situ tests: standard penetration tests (SPT) and cone penetration tests (CPT). The results analyzed here are part of a study carried out on the Santo Tirso landfill (north of Portugal) between 2001 and 2007. The influence of the strain levels, waste composition, and waste age on the shear strength parameters is presented, as well as an attempt to establish some correlations between the SPT and CPT tests and to estimate municipal solid waste (MSW) friction angles from the SPT tests. The results indicate that the aging of the waste, which is characterized by a decrease in fibrous and organic materials and an increase in inert materials and fine fraction, leads to an increase in frictional resistance and to a decrease in cohesion. The results of the SPT and CPT tests indicate higher penetration resistance in older and deeper waste. Estimating the frictional resistance from the SPT test seems to obey an empirical relationship expressed by a power function, which depends on the strain level.

Implications: Comparison of shear strength parameters of municipal solid waste (MSW) determined through laboratory (triaxial tests) and in situ tests (SPT and CPT) showed that the greater amount of fibrous and granular elements leads to an increase in “cohesion” and in friction angle values, respectively. Waste aging results in an increase in frictional resistance and in a decrease in “cohesive” resistance. This is consistent with the composition changes with aging: increase of the relative quantity of inert materials and fine fraction, and decrease in particle size, in organic matter content, and in fabrics and plastics.  相似文献   
93.
Gill anomalies in two fish species (Geophagus brasiliensis and Astyanax bimaculatus) were compared among three freshwater systems with different water quality: one eutrophic river, one eutrophic reservoir, and one oligotrophic reservoir. The raised hypotheses are that reservoirs with low water quality (eutrophic) have fish with more gills anomalies compared with reservoirs with high water quality (oligotrophic), and that the more stable environmental conditions of eutrophic rivers have fish with better healthy conditions than eutrophic reservoirs that have lesser stable environmental conditions. Gills of 36 adult individuals of G. brasiliensis and 23 of A. bimaculatus collected during the winter 2008 and winter 2009 were examined, and the proportions of occurrence of nine histological alterations were compared for the two species among the three systems using a binomial t test for independent samples. Histological changes in fish gills that are reversible and unspecific, such as epithelial lifting, interstitial edema, leukocyte infiltration, hyperplasia of the epithelial cells, lamellar fusion, and vasodilatation were common in both fish species in the three systems. However, lamellar aneurism, which is a more serious and often irreversible anomaly, and lamellar blood congestion occurred only in fish from the two reservoirs. Alternatively, necrosis occurred more in fish from the river. Fish gill anomalies in both species did not differ between the two reservoirs, despite having different water quality. We rejected the hypothesis that reservoirs with lower water quality have fish with more gill injuries compared with high water quality reservoirs. Moreover, the eutrophic river seems to affect differently the healthy condition of fish species, compared with the eutrophic reservoir.  相似文献   
94.
The water reservoir of Vargem das Flores, Brazil, has been subject to eutrophication problems. The occurrence of cyanobacterial blooms in this water body has raised concerns regarding the presence of toxic metabolites. In order to understand the factors that promote the proliferation and distribution of cyanobacteria in the reservoir, physicochemical parameters, species composition, and toxicity of the reservoir water column were analyzed at monthly intervals over a 3-year period (2004-2007) using a range of analytical techniques. The results showed that cyanobacteria were absent in the dry period, returning after the onset of stratification. A succession pattern was observed within this group. The Aphanocapsa genus was dominant in the last rainy period of the study (October 2006 to March 2007). However toxicity was only detected when the genera Microcystis and Sphaerocavum were present (October 2005). The principal components analysis showed negative correlation between cyanobacteria and orthophosphate. The change of dominant cyanobacteria along the 3 years of study and the final prevalence of nontoxic genera in the reservoir is an evidence of water quality improvement in response to the management techniques implemented in the reservoir basin.  相似文献   
95.
Despite the classification as known or suspected human carcinogens, by the International Agency for Research on Cancer, the antineoplastic drugs are extensively used in cancer treatment due to their specificity and efficacy. As human carcinogens, these drugs represent a serious threat to the healthcare workers involved in their preparation and administration. This work aims to contribute to better characterize the occupational exposure of healthcare professionals to antineoplastic drugs, by assessing workplace surfaces contamination of pharmacy and administration units of two Portuguese hospitals. Surface contamination was assessed by the determination of cyclophosphamide, 5-fluorouracil, and paclitaxel. These three drugs were used as surrogate markers for surfaces contamination by cytotoxic drugs. Wipe samples were taken and analyzed by HPLC-DAD. From the total of 327 analyzed samples, in 121 (37 %) was possible to detect and quantify at least one drug. Additionally, 28 samples (8.6 %) indicate contamination by more than one antineoplastic drug, mainly in the administration unit, in both hospitals. Considering the findings in both hospitals, specific measures should be taken, particularly those related with the promotion of good practices and safety procedures and also routine monitoring of surfaces contamination in order to guarantee the appliance of safety measures.  相似文献   
96.
For many millennia humans and reptiles have interacted, but the attitude of humans towards these animals has depended on culture, environment, and personal experience. At least 719 reptile species are known to occur in Brazil and about 11% of this fauna has been exploited for many different purposes, including bushmeat, leather, ornamental and magic/religious uses, and as folk medicines. Brazil can therefore serve as an interesting case study for better understanding reptile use by human societies, and the present paper catalogues some of the reptile species being used in Brazil and discusses implications for their conservation. A literature review indicated that 81 reptile species are culturally important in this country, with 47 (58%) species having multiple uses, 54 being used for medicinal purposes, 38 as food, 28 for ornamental or decorative purposes, 20 used in magic/religious practices, 18 as pets, and 40 are commonly killed when they come into contact with humans. Regarding their conservation status, 30 (37.5%) are included on State's Red List, Brazilian Red List or the IUCN Red List. There are many forms of interaction between reptiles and humans in Brazil-although most of them are quite negative in terms of wildlife conservation-which reinforces the importance of understanding such uses and interactions in the context of protecting reptiles in Brazil. A better understanding of the cultural, social, and traditional roles of these reptiles is fundamental to establishing management plans for their sustainable use.  相似文献   
97.
In general, tropical rivers have a great impact on human activities. Bioaccumulation of toxins is a worldwide problem nowadays and has been, historically, overlooked by the supervisory authorities. This study evaluated cytogenotoxic effects of Guaribas river (a Brazilian river) water during dry and rainy seasons of 2014 by using the Allium cepa test system. The toxicogenetic variables, including root growth, mitotic index, and chromosomal aberrations, were analyzed in meristematic cells of A. cepa exposed to water samples taken from the up-, within, and downstream of the city Picos (state: Piauí). The physical-chemical parameters were also analyzed to explain water quality and possible anthropogenic action. Additionally, the presence of heavy metals was also analyzed to explain water quality and possible damaging effects on eukaryotic cells. The results suggest that the river water exerted cytotoxic, mutagenic, and genotoxic effects, regardless of the seasons. In addition, Guaribas river presented physico-chemical values outside the Brazilian laws, which can be a characteristic of human pollution (domestic sewage, industrial, and local agriculture). The genetic damage was positively correlated with higher levels of heavy metals. The pollution of the Guaribas river water may link to the chemical contamination, including the action of heavy metals and their impacts on genetic instability in the aquatic ecosystem. In conclusion, necessary steps should be taken into account for further toxicogenetic studies of the Guaribas river water, as it has an influence in human health of the same region of Brazil.  相似文献   
98.
99.
100.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号