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   199篇
  免费   6篇
  国内免费   3篇
安全科学   4篇
废物处理   2篇
环保管理   25篇
综合类   29篇
基础理论   43篇
环境理论   1篇
污染及防治   70篇
评价与监测   10篇
社会与环境   19篇
灾害及防治   5篇
  2022年   4篇
  2021年   8篇
  2020年   8篇
  2019年   6篇
  2018年   14篇
  2017年   6篇
  2016年   11篇
  2015年   8篇
  2014年   9篇
  2013年   14篇
  2012年   9篇
  2011年   23篇
  2010年   12篇
  2009年   12篇
  2008年   14篇
  2007年   9篇
  2006年   12篇
  2005年   9篇
  2004年   3篇
  2003年   6篇
  2001年   1篇
  2000年   3篇
  1999年   1篇
  1998年   1篇
  1997年   1篇
  1963年   1篇
  1960年   1篇
  1958年   1篇
  1946年   1篇
排序方式: 共有208条查询结果,搜索用时 114 毫秒
191.
Copper and iron isotope fractionation by plant uptake and translocation is a matter of current research. As a way to apply the use of Cu and Fe stable isotopes in the phytoremediation of contaminated sites, the effects of organic amendment and microbial addition in a mine-spoiled soil seeded with Helianthus annuus in pot experiments and field trials were studied. Results show that the addition of a microbial consortium of ten bacterial strains has an influence on Cu and Fe isotope fractionation by the uptake and translocation in pot experiments, with an increase in average of 0.99?‰ for the δ65Cu values from soil to roots. In the field trial, the amendment with the addition of bacteria and mycorrhiza as single and double inoculation enriches the leaves in 65Cu compared to the soil. As a result of the same trial, the δ56Fe values in the leaves are lower than those from the bulk soil, although some differences are seen according to the amendment used. Siderophores, possibly released by the bacterial consortium, can be responsible for this change in the Cu and Fe fractionation. The overall isotopic fractionation trend for Cu and Fe does not vary for pot and field experiments with or without bacteria. However, variations in specific metabolic pathways related to metal–organic complexation and weathering can modify particular isotopic signatures.  相似文献   
192.
A massive earthquake off the west coast of Sumatra in Indonesia triggered a tsunami on 26 December 2004. At least five million people around the world were affected, and the total number of deaths exceeded 280,000. In Thailand, the tsunami struck six southern provinces, where the disaster's immediate impact was catastrophic. Based on ethnographic fieldwork in Phang Nga Province (2007), this paper provides an overview of the disaster's psychosocial consequences for Thai health service providers, the vast majority of whom were bypassed by regional post-tsunami mental health initiatives. The available tsunami literature only briefly attends to health providers' experience of professional 'burn-out', rather than explores the tsunami's wide spectrum of psychosocial effects. This research aims to remedy such oversights through 'critical medical' and 'interpretive phenomenological' analysis of the diverse and culturally-situated ways in which health providers' experienced the tsunami. The paper concludes by arguing for disaster-related psychosocial interventions to involve health providers explicitly.  相似文献   
193.
To facilitate the choice of more sustainable animal-based products in the diet, a Swedish meat guide providing complex, multi-layered environmental information to non-experts has been developed. This study evaluated reception of this guide by consumers. In five focus groups, participants (“interested consumers”) carried out a joint environmental and animal welfare ranking assignment to test understanding and use of the guide. The type and detail of indicators (e.g. carbon footprint) in the meat guide suited the audience. The guide stimulated discussion on ethical issues and quality aspects of meat, revealed perceived obstacles to reducing meat consumption and provided an understanding that any food product chosen comes with trade-offs.  相似文献   
194.

Purpose  

The aim of the present study is to propose a nonlinear model which provides an indicator for the maximum phytoextraction of metals to help in the decision-making process. Research into different species and strategies plays an important role in the application of phytoextraction techniques to the remediation of contaminated soil. Also, the convenience of species according to their biomass and pollutant accumulation capacities has gained important space in discussions regarding remediation strategies, whether to choose species with low accumulation capacities and high biomass or high accumulation capacities with low biomass.  相似文献   
195.
Rapid environmental change in vulnerable destinations has stimulated a new form of travel termed “last chance tourism” (LCT). Studies have examined the risks of LCT, while leaving potential opportunities within this new tourism market largely underexplored. Results of survey (n?=?399) research in Jasper National Park, Canada reveal that a LCT motivation influences decisions to visit this iconic Canadian destination, and suggest that this motivation is linked to a desire to learn about the impacts of climate change on the Athabasca Glacier. Findings suggest there may be short to medium term opportunities associated with LCT, including promoting climate change ambassadorship through management interventions. This paper discusses a range of possible education, interpretive, and outreach activities that might be employed at LCT destinations. It outlines the relative merits (or what we refer to as “uneasy benefits”) of promoting the glacier and other LCT destinations within a protected areas management and climate change adaptation context.  相似文献   
196.
Halogenated 1'methyl-1,2'-bipyrroles (MBPs) have been identified worldwide in marine mammals. Here we present the tentative identification of previously undetected MBP congeners in Delpinus delphis blubber using gas chromatography/electron capture negative ion mass spectrometry (GC/ECNI-MS) and comprehensive two-dimensional gas chromatography/time of flight mass spectrometry (GCxGC/TOF-MS). This is the first report of 26 congeners. The presence of numerous partially halogenated congeners suggests that they are either biosynthesized concomitantly with their perhalogenated counterparts or that their dehalogenation products can also bioaccumulate. The newly found compounds fit the geographic trend that has been previously noted. That is, samples from the Atlantic Ocean are dominated by the more brominated congeners while those from the Pacific are dominated by the more chlorinated congeners.  相似文献   
197.
We determined metal contents of co-occurring algae Padina crassa and Sargassum sp. in Port Jackson (Australia), and relationships between metal levels and the abundance of epifaunal amphipods. Copper, lead and zinc concentrations were amongst the highest yet recorded in these algae. Copper, manganese and lead concentrations were far greater in P. crassa than Sargassum sp., possibly due to the low growth of P. crassa in proximity to contaminated sediments. However, in manipulative experiments the proximity of algae to sediments did not explain these differences. The abundance of herbivorous amphipods correlated negatively with the copper content of P. crassa, but not with the lower concentrations in Sargassum sp. The greater contamination of P. crassa led to patchy distributions of metals in algal beds and recolonisation experiments showed Sargassum sp. acts as a refuge from contaminants for epifauna. The contamination of macroalgae may pose threats to epifauna in harbours around the world.  相似文献   
198.
The potential adverse health effects of PM2.5 (particulate matter with an aerodynamic diameter <2.5 μm) and vapor samples from three communities that neighbor railyards, Commerce (CM), Long Beach (LB), and San Bernardino (SB), were assessed by determination of chemical reactivities attributed to the induction of oxidative stress by air pollutants. The assays used were dithiothreitol (DTT)- and dihydrobenzoic acid (DHBA)-based procedures for prooxidant content and a glyceraldehyde-3-phosphate dehydrogenase (GAPDH) assay for electrophiles. Prooxidants and electrophiles have been proposed as the reactive chemical species responsible for the induction of oxidative stress by air pollution mixtures. The PM2.5 samples from CM and LB sites showed seasonal differences in reactivities, with higher levels in the winter, whereas the SB sample differences were reversed. The reactivities in the vapor samples were all very similar, except for the summer SB samples, which contained higher levels of both prooxidants and electrophiles. The results suggest that the observed reactivities reflect general geographical differences rather than direct effects of the railyards. Distributional differences in reactivities were also observed, with PM2.5 fractions containing most of the prooxidants (74–81%) and the vapor phase most of the electrophiles (82–96%). The high levels of the vapor-phase electrophiles and their potential for adverse biological effects point out the importance of the vapor phase in assessing the potential health effects of ambient air.

Implications:?PM2.5 and its corresponding vapor phase, containing semivolatile organics, were collected in three communities in the Los Angeles Basin and examined with toxicologically relevant chemical assays. The PM2.5 phase contained most of the prooxidants and the vapor phase contained most of the electrophiles, whose content was highest in summer samples from a receptor site that reflected greater photochemical processing of the air parcel during its transport. As electrophiles initiate both adverse and adaptive responses to foreign substances by biological systems, their presence in the vapor phase emphasizes the importance of this phase in the overall health effects of ambient air.  相似文献   
199.
Mercury is a globally distributed, environmental contaminant. Quantifying the retention and loss of mercury is integral for predicting mercury-sensitive ecosystems. There is little information on how dissolved organic carbon(DOC) concentrations and particulates affect mercury photoreaction kinetics in freshwater lakes. To address this knowledge gap,samples were collected from ten lakes in Kejimkujik National Park, Nova Scotia(DOC: 2.6–15.4 mg/L). Filtered(0.2 μm) and unfiltered samples were analysed for gross photoreduction, gross photooxidation, and net reduction rates of mercury using pseudo first-order curves. Unfiltered samples had higher concentrations(p = 0.04) of photoreducible divalent mercury(Hg(II)RED)(mean of 754 ± 253 pg/L) than filtered samples(mean of 482 ± 206 pg/L);however, gross photoreduction and photooxidation rate constants were not significantly different in filtered or unfiltered samples in early summer. DOC was not significantly related to gross photoreduction rate constants in filtered(R~2= 0.43; p = 0.08) and unfiltered(R~2= 0.02; p = 0.71) samples; DOC was also not significantly related to gross photooxidation rate constants in filtered or unfiltered samples. However, DOC was significantly negatively related with Hg(Ⅱ)_(RED) in unfiltered(R2= 0.53; p = 0.04), but not in filtered samples(R~2= 0.04;p = 0.60). These trends indicate that DOC is a factor in determining dissolved mercury photoreduction rates and particles partially control available Hg(Ⅱ)_(RED) in lake water. This research also demonstrates that within these lakes gross photoreduction and photooxidation processes are close to being in balance. Changes to catchment inputs of particulate matter and DOC may alter mercury retention in these lakes and could partially explain observed increases of mercury accumulation in biota.  相似文献   
200.
Even though the global COVID-19 pandemic may affect how medical care is delivered in general, most countries try to maintain steady access for women to routine pregnancy care, including fetal anomaly screening. This means that, also during this pandemic, fetal anomalies will be detected, and that discussions regarding invasive genetic testing and possibly fetal therapy will need to take place. For patients, concerns about Severe Acute Respiratory Syndrome-Corona Virus 2 will add to the anxiety caused by the diagnosis of a serious fetal anomaly. Yet, also for fetal medicine teams the situation gets more complex as they must weigh up the risks and benefits to the fetus as well as the mother, while managing a changing evidence base and logistic challenges in their healthcare system.  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