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   83篇
  免费   3篇
安全科学   2篇
废物处理   2篇
环保管理   17篇
综合类   12篇
基础理论   32篇
污染及防治   9篇
评价与监测   8篇
社会与环境   4篇
  2022年   1篇
  2021年   3篇
  2018年   2篇
  2017年   3篇
  2016年   4篇
  2015年   4篇
  2014年   4篇
  2013年   7篇
  2012年   6篇
  2011年   5篇
  2010年   1篇
  2009年   2篇
  2008年   2篇
  2007年   7篇
  2006年   4篇
  2004年   2篇
  2002年   2篇
  2001年   2篇
  2000年   3篇
  1998年   3篇
  1997年   1篇
  1996年   1篇
  1993年   1篇
  1990年   1篇
  1989年   2篇
  1988年   1篇
  1987年   1篇
  1986年   1篇
  1985年   2篇
  1981年   1篇
  1975年   1篇
  1973年   3篇
  1972年   1篇
  1968年   1篇
  1957年   1篇
排序方式: 共有86条查询结果,搜索用时 15 毫秒
71.
The balance of fresh and saline water is essential to estuarine ecosystem function. Along the fresh-brackish-saline water gradient within the C-43 canal/Caloosahatchee River Estuary (CRE), the quantity, timing and distribution of water, and associated water quality significantly influence ecosystem function. Long-term trends of water quality and quantity were assessed from Lake Okeechobee to the CRE between May 1978 and April 2016. Significant changes to monthly flow volumes were detected between the lake and the estuary which correspond to changes in upstream management. and climatic events. Across the 37-year period, total phosphorus (TP) flow-weighted mean (FWM) concentration significantly increased at the lake; meanwhile, total nitrogen (TN) FMW concentrations significantly declined at both the lake and estuary headwaters. Between May 1999 and April 2016, TN, TP, and total organic carbon (TOC), ortho-P, and ammonium conditions were assessed within the estuary at several monitoring locations. Generally, nutrient concentrations decreased from upstream to downstream with shifts in TN/TP from values >?20 in the freshwater portion, ~?20 in the estuarine portion, and <?20 in the marine portion indicating a spatial shift in nutrient limitations along the continuum. Aquatic productivity analysis suggests that the estuary is net heterotrophic with productivity being negatively influenced by TP, TN, and TOC likely due to a combination of effects including shading by high color dissolved organic matter. We conclude that rainfall patterns, land use, and the resulting discharges of runoff drive the ecology of the C-43/CRE aquatic continuum and associated biogeochemistry rather than water management associated with Lake Okeechobee.  相似文献   
72.
Beekeepers are central to pollinator health. For policymakers and beekeeping organisations to develop widely accepted strategies to sustain honeybee populations alongside wild pollinators, a structured understanding of beekeeper motivations is essential. UK beekeepers are increasing in number, with diverse management styles despite calls for coordinated practice to manage honeybee health. Our Q methodology study in Cornwall, UK, indicated five beekeeping perspectives; conventional hobbyists, natural beekeepers, black bee farmers, new-conventional hobbyists and pragmatic bee farmers. Motivations can be shared across perspectives but trade-offs (notably between economic, social responsibility and ideological motivations) result in differing practices, some of which counter ‘official’ UK advice and may have implications for pollinator health and competition. Honeybee conservation emerged as a key motivator behind non-conventional practices, but wild pollinator conservation was not prioritised by most beekeepers in practice. Q methodology has the potential to facilitate non-hierarchical collaboration and conceptualisation of sustainable beekeeping, moving towards co-production of knowledge to influence policy.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-022-01736-w.  相似文献   
73.
The risk to non-human biota from exposure to ionizing radiation is of current international interest. In calculating radiation doses to humans, it is common to multiply the absorbed dose by a factor to account for the relative biological effectiveness (RBE) of the radiation type. However, there is no international consensus on the appropriate value of such a factor for weighting doses to non-human biota. This paper summarizes our review of the literature on experimentally determined RBEs for internally deposited alpha-emitting radionuclides. The relevancy of each experimental result in selecting a radiation weighting factor for doses from alpha particles in biota was judged on the basis of criteria established a priori. We recommend a nominal alpha radiation weighting factor of 5 for population-relevant deterministic and stochastic endpoints, but to reflect the limitations in the experimental data, uncertainty ranges of 1-10 and 1-20 were selected for population-relevant deterministic and stochastic endpoints, respectively.  相似文献   
74.
We report the prenatal diagnosis of trisomy 6 mosaicism via amniocentesis, in which trisomy 6 cells were identified in three of five culture vessels with 33% (5/15) of colonies showing trisomic cells. The pregnancy was electively terminated and examination revealed minor abnormalities (shortening of the femurs, micrognathia, posterior malrotation of the ears, and bilateral camptomelia of the second digit of the hands and fifth digits of the feet). Cytogenetic analysis of the placenta showed trisomy 6 in 100% of 20 cells studied. Karyotype was 46,XX in 100 cells examined from fetal skin. There are relatively few prenatally diagnosed cases of mosaic trisomy 6 at amniocentesis. Confined placental mosaicism (CPM) has been postulated in other cases where follow-up cytogenetic studies were not available. The present case differs from those previously reported, as it appears to represent CPM of chromosome 6 with phenotypic effects to the fetus. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   
75.
Seasonal variations in the concentrations of groundwater with respect to arsenic, lead, cadmium and aluminium has been studied in Dhemaji district of Assam, India. The water samples were collected from 20 different sites in both dry and wet seasons. The metals were analysed by using atomic absorption spectrometer, Perkin Elmer AAnalyst 200 model. The concentrations of aluminium, lead and cadmium in groundwater were found to be significantly elevated. High concentrations of all the metals were recorded in the dry season than in the wet season. Univariate statistics along with skewness, kurtosis and confidence limit have been calculated for both the seasons to test the distribution normality for each metal. Statistical analyses of the data reveal non-uniform distribution of the metals in the area. The metal contamination of groundwater in the district follows the trend Al > Pb > Cd > As in both the seasons.  相似文献   
76.
This article examines the “climate gap” in the Southwest US (Arizona and New Mexico), referring to the “disproportionate and unequal implications of climate change and climate change mitigation” for “people of color and the poor” [Shonkoff, S.B., et al., 2011. The climate gap: environmental health and equity implications of climate change mitigation policies in California. Climatic Change, 109 (Suppl. 1), S485–S503]. The climate and poverty relationship is examined using multi-scaled analysis across three indicators of climate vulnerability, focusing on connections to health, food, and energy during the period 2010–2012. We provide an overview of climate-related social vulnerability in the Southwest based on available federal, state, and county-level census data. We then summarise the results from a stakeholder workshop and in-depth interviews about climate vulnerabilities with social service providers in southern Arizona. We identify a significant Southwest climate gap based on census data and interview findings about climate vulnerability especially relating to high levels of poverty, health disparities, and increasing costs for energy, water, and food. We find that grassroots and community organisations have mobilised to respond to climate and social vulnerability, yet resources for mitigation and adaptation are insufficient given the high level of need. Confronting a changing climate that is projected to be hotter, drier, and with the potential to reach new thresholds, we suggest that more research needs to be done to understand the social and spatial characteristics of climate risk and how low-income populations embody and experience climate risk, and adapt to a changing climate.  相似文献   
77.
In this paper the results of sampling for trace chlorinated organics at two municipal refuse incinerators in Ontario are presented. The information may be of Interest to individuals concerned with the assessment of PCDD/PCDF (polychlorinated dibenzo-p-dioxin/polychlorinated dibenzofuran) emissions from incineration of refuse and their impact on the energyfrom- waste program. PCDDs, PCDFs, PCBs (polychlorinated biphenyls), CBs (chlorobenzenes) and CPs (chlorophenols) were quantified in all process streams including refuse, ash and stack emissions. Manual sorting of refuse and collection of ash samples were carried out simultaneously with three 24-hour continuous stack sampling tests at each plant. The results suggested that the total output of PCDDs and PCDFs varied proportionately with their input at both incinerators. However, the input of PCDDs/PCDFs could not account for their total output. The chemistry of PCDDs/PCDFs in the input and output streams were different in that only heptachlorinated and octachlorinated species were present in significant quantities in the refuse while lower chlorinated species were predominant in stack emissions and ash streams. There was no correspondence between the Input of PCBs/CBs/CPs and the output of PCDDs/PCDFs. The output of PCDDs/PCDFs, however, varied Inversely with the total output of PCBs/CBs/CPs, suggesting that the latter compounds could have been partially responsible for the formation of PCDDs and PCDFs. The PCDF emissions were also affected by combustion conditions; they were higher in magnitude and consisted of predominantly tetrachlorinated and pentachlorinated species at the plant where the combustion temperatures were lower.  相似文献   
78.
This paper presents a survey of pesticide residues in tanks following application and throughout the cleanout procedure as conducted by 46 volunteer operators across Colorado. While many pesticides were detected, this paper focuses on dicamba and 2,4-D, which were detected by liquid chromatography/tandem mass spectroscopy (LC-MS/MS). An exponential decrease in concentration was observed with sequential rinses, although this decrease may be more rapid for more water-soluble pesticides. More than 95% of the pesticide in the prerinse solution was removed by the end of the third rinse in all but three operator samples. Concentrations after three rinses were 0.41 ± 0.25 and 3.3 ± 1.1 mg/L for dicamba and 2,4-D, respectively. These concentrations suggest that the recommended practice of three rinses may not be adequate to eliminate off-target effects or point sources of pesticide waste, and that the recommended standard of personal protective equipment is essential to prevent worker exposure to the chemicals.

Implications:?This paper demonstrates that the waste generated during cleanout of pesticide application devices constitutes a potential source of pollution and worker exposure. In particular, while the first rinse of pesticide containers is often treated as hazardous waste and reapplied to crops, the remaining rinses are not. This work demonstrates that the wastewater generated in subsequent rinses can have high enough concentrations to impact worker health, cause off-target effects on crops, and potentially constitute a point source of pesticides. The practical implication is for improved recommendations and regulations regarding pesticide applicators and their cleanout process.  相似文献   
79.
/ We examined data relative to species abundance, distribution, anddiversity patterns of reptiles and amphibians to determine how perceptionschange over time and with level of sampling effort. Location data werecompiled on more than one million individual captures or observations of 98species during a 44-year study period on the US Department of Energy's(DOE) Savannah River Site National Environmental Research Park (SRS-NERP) inSouth Carolina. We suggest that perceptions of herpetofaunal speciesdiversity are strongly dependent on level of effort and that land managementdecisions based on short-term data bases for some faunal groups could resultin serious errors in environmental management. We provide evidence thatacquiring information on biodiversity distribution patterns is compatiblewith multiyear spatially extensive research programs and also provide aperspective of what might be achieved if long-term, coordinated researchefforts were instituted nationwide.To conduct biotic surveys on government-managed lands, we recommend revisionsin the methods used by government agencies to acquire and report biodiversitydata. We suggest that government and industry employees engaged inbiodiversity survey efforts develop proficiency in field identification forone or more major taxonomic groups and be encouraged to measure the status ofpopulations quantitatively with consistent and reliable methodologies. Wealso suggest that widespread academic cooperation in the dissemination ofinformation on regional patterns of biodiversity could result byestablishment of a peer-reviewed, scientifically rigorous journal concernedwith status and trends of the biota of the United States. KEY WORDS: Abundance; Amphibian; Biodiversity; Distribution; Landmanagement; Reptile  相似文献   
80.
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