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   247篇
  免费   3篇
  国内免费   1篇
安全科学   2篇
废物处理   18篇
环保管理   23篇
综合类   25篇
基础理论   32篇
污染及防治   107篇
评价与监测   28篇
社会与环境   16篇
  2023年   8篇
  2022年   16篇
  2021年   27篇
  2020年   14篇
  2019年   8篇
  2018年   13篇
  2017年   12篇
  2016年   17篇
  2015年   9篇
  2014年   20篇
  2013年   24篇
  2012年   9篇
  2011年   12篇
  2010年   11篇
  2009年   10篇
  2008年   10篇
  2007年   6篇
  2006年   4篇
  2005年   4篇
  2004年   2篇
  2003年   4篇
  2002年   5篇
  2001年   1篇
  1998年   1篇
  1990年   1篇
  1976年   1篇
  1970年   1篇
  1957年   1篇
排序方式: 共有251条查询结果,搜索用时 31 毫秒
161.
The feeding preferences of the coastal dolphins Pontoporia blainvillei and Sotalia guianensis in south-eastern Brazil (21o18′S–22o25′S) were assessed through the prey’s index of relative importance (IRI), total mercury concentration (Hgtot), and stable isotopic (δ15N and δ13C) to compare their efficiency in the discrimination of prey contribution to the predators’ diet. The IRI was the best tool to describe the dolphins’ preference, while Hgtot and δ15N seemed to be efficient as a trophic marker when the diet is made up of prey of varying sizes, as observed in S. guianensis. Both dolphins presented lighter δ15N than their prey species, which is an unusual pattern. However, as the sample size to isotope ratios analysis was small, especially to the dolphins, the results should be considered with caution, and further studies are necessary to corroborate these findings. The δ13C values characterized a typical coastal food chain, confirming the preferential area of these species.  相似文献   
162.
Toxicity of lead in soil is well documented and established. Phytoremediation has gained attention as a cheap, easily applicable, and eco-friendly clean-up technology. Chemical methods are used to assess exact levels and type of pollutants but heavy metal content in soil can also be evaluated indirectly by estimation of phytotoxicity levels using bioassays. Plant bioassays through fast germinating cereals can indicate not only the level of pollution and its effects on growth and survival but also the progress of phytoremediation process. The performance of barley Hordeum vulgare L. seedlings as bioassay for assessment of changes in the levels of lead (Pb) at three concentrations, i.e., 300 (T1), 600 (T2), and 1,200 ppm (T3) in the soil was evaluated while testing the efficiency of Crinum asiaticum L. as a phytoremedial tool. At the first assessment, i.e., 30 DAT (days after treatment) shoot and root lengths of seedlings decreased with increasing concentrations of Pb. As the study progressed, a decrease in levels of Pb was accompanied by better germinability and growth of barley. At 120 DAT seedling growth in all the treatments were comparable to control. In T1, T2, and T3 soils, 74.5%, 83.7%, and 91.2% reduction in lead content was observed at 120 DAT. Highly significant correlations between decreasing pollutant (Pb) content in the soil, seed germination, and seedling growth of barley H. vulgare were found. The differences in root and shoot length as well as overall growth pattern are indicative of the suitability of barley as a bio-monitoring tool.  相似文献   
163.
The present study evaluated the mutagenic potential of surface water from the Lucrecia dam. The Tradescantia-micronucleus (Trad-MCN) test and CBMN assay in human peripheral blood lymphocytes were applied, corresponding to an in vivo and in vitro system, respectively. Heavy metals and some physicochemical properties were also measured. Water samples were collected in November 2009 (dry season) and May 2010 (rainy season) at three different points. Results of both assays for raw water showed positive responses for the points analyzed when compared to the negative control. The CBMN assay showed that diluted water was still able to induce a significant increase in micronucleus frequency. For both assays, the highest mean MN was observed in the dry season. Chemical analyses detected an increase in heavy metal levels at the sampling points and in the different seasons. These findings indicate the presence of genotoxins, such as heavy metals, in the water, which may be affecting the entire ecosystem, as well as human health. More prolonged monitoring is recommended in order to better characterize this public water supply.  相似文献   
164.
Food and Environmental Virology - Oysters are filter-feeders and retain sewage-derived pathogens in their organs or tissues. Since most enteric viruses involved in outbreaks cannot grow in cell...  相似文献   
165.
Environmental Science and Pollution Research - Chitosan induces tolerance to abiotic stress agents in plants. However, studies on the different application forms of this biopolymer are limited....  相似文献   
166.

The applicability of cellulose nanofibrils (CNFs) has received attention due to their attractive properties. This study proposes the functionalization of açai CNFs with copaiba oil and vegetal tannins to produce films with potential for packaging. Bio-based films were evaluated by vapor permeability, colorimetry, and mechanical strength. CNFs were produced by mechanical fibrillation, from suspensions of bleached açai fibers and commercial eucalipytus pulp. Moreover, copaiba oil and vegetal tannin were added to the CNFs to produce films/nanopapers by casting from both suspensions with concentrations of 1% (based on CNF dry mass). The bulk densities of the eucalyptus CNF films were higher (1.126–1.171 g cm?3) compared to the açai CNF ones. Films from eucalyptus and açai pulps containing copaiba oil and tannins presented higher Tonset and Tmax, respectively (312 and 370 °C). Films with açaí CNFs functionalized with copaiba oil and tannin showed the lowest permeability value (370 g day?1 m?2). Films produced with eucalyptus pulp, and eucalyptus pulp functionalized with copaiba oil highlighted by superior mechanical strength, achieving 133.8 and 121.4 MPa, respectively. The evaluation of colorimetry showed a greater tendency to yellowing for açai films, especially those functionalized with vegetal tannins. Besides the low cost, functionalized vegetal-based nanomaterials could have attractive properties, with potential for application as some kind of packaging, for transporting basic products, such as breads, flours, or products with low moisture content, enabling efficient utilization of forest wastes.

  相似文献   
167.
Environmental Science and Pollution Research - This work investigated an innovative alternative to improve municipal wastewater treatment plant effluent (MWWTP effluent) quality aiming at the...  相似文献   
168.
Environmental Science and Pollution Research - The sensitivity of anuran to the effects of habitat destruction and contamination has led to a preoccupying global decline in their populations....  相似文献   
169.
The promotion of a better rational use of water in industry requires an adequate knowledge of aqueous streams inside industrial plants. The main difficulty found in this respect is a lack of accurate measurement of such streams. In order to overcome this difficulty, a water balance tool with data reconciliation is used. This paper presents a method based on the idea that an estimated assumption can be made for any flow rate based on the best available information (quality of information). The quality of information is inversely proportional to the uncertainty of the estimated or measured flow rate and therefore there is a proportionality constant that relates these two. This paper demonstrates that the values of the proportionality constants in the real system are proximally the same for any stream. Furthermore, the proposed method has been applied to real systems with very poor measurement. This method enables the data reconciliation from water balances without data redundancy and without having to ignore flow rates with high levels of uncertainty.  相似文献   
170.
The Brazilian Amazon is a globally important ecosystem that is undergoing rapid development and land-use change. Roads are a key spatial determinant of land-use conversion and strongly influence the rates and patterns of habitat loss and represent a key component of models that attempt to predict the spatio-temporal patterns of Amazonian land-use change and the consequences of such changes. However, the spatio-temporal patterns of road network development are poorly understood and seldom quantified. Here, we used manually digitised satellite imagery at multiple temporal and spatial scales across the Brazilian Amazon to quantify and model the rate at which road networks are proliferating. We found that the road network grew by almost 17,000 km per year between 2004 and 2007. There was large spatial variation in road network density, with some municipalities having road densities as high as 0.5 km/km2, and road network growth rates were highest in municipalities with an intermediate road network density. Simulations indicated that road network development within municipalities follows a logistic growth pattern through time, with most of the development occurring within a 39-year time period. This time period is similar to those of other boom and bust development dynamics observed in the Brazilian Amazon. Understanding the temporal patterns of road development will aid the development of better predictive land-use change models for the Amazon, given the key importance of roads as a predictor of deforestation in many existing models.  相似文献   
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