全文获取类型
收费全文 | 645篇 |
免费 | 32篇 |
国内免费 | 9篇 |
专业分类
安全科学 | 30篇 |
废物处理 | 19篇 |
环保管理 | 159篇 |
综合类 | 88篇 |
基础理论 | 220篇 |
污染及防治 | 112篇 |
评价与监测 | 32篇 |
社会与环境 | 16篇 |
灾害及防治 | 10篇 |
出版年
2023年 | 5篇 |
2022年 | 17篇 |
2021年 | 13篇 |
2020年 | 23篇 |
2019年 | 18篇 |
2018年 | 21篇 |
2017年 | 38篇 |
2016年 | 24篇 |
2015年 | 23篇 |
2014年 | 29篇 |
2013年 | 44篇 |
2012年 | 41篇 |
2011年 | 47篇 |
2010年 | 38篇 |
2009年 | 31篇 |
2008年 | 34篇 |
2007年 | 36篇 |
2006年 | 26篇 |
2005年 | 20篇 |
2004年 | 19篇 |
2003年 | 21篇 |
2002年 | 17篇 |
2001年 | 10篇 |
2000年 | 7篇 |
1999年 | 10篇 |
1998年 | 9篇 |
1997年 | 10篇 |
1996年 | 3篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有686条查询结果,搜索用时 646 毫秒
591.
Trace metal enrichments in core sediments in Muthupet mangroves, SE coast of India: application of acid leachable technique 总被引:2,自引:0,他引:2
Janaki-Raman D Jonathan MP Srinivasalu S Armstrong-Altrin JS Mohan SP Ram-Mohan V 《Environmental pollution (Barking, Essex : 1987)》2007,145(1):245-257
Core sediments from Mullipallam Creek of Muthupet mangroves on the southeast coast of India were analyzed for texture, CaCO(3), organic carbon, sulfur and acid leachable trace metals (Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn and Cd). Textural analysis reveals a predominance of mud while CaCO(3) indicates dissolution in the upper half of the core, and reprecipitation of carbonates in reduction zones. Trace metals are diagenetically modified and anthropogenic processes control Pb and, to some extent, Ni, Zn and Fe. A distinct event is identified at 90 cm suggesting a change in deposition. Strong relationship of trace metals with Fe indicates that they are associated with Fe-oxyhydroxides. The role of carbonates in absorbing trace metals is evident from their positive relationship with trace metals. Comparison of acid leachable trace metals indicates increase in concentrations in the study area and the sediments act as a sink for trace metals contributed from multiple sources. 相似文献
592.
Verreault J Bech C Letcher RJ Ropstad E Dahl E Gabrielsen GW 《Environmental pollution (Barking, Essex : 1987)》2007,145(1):138-145
Exposure to organohalogens in endotherms has been suggested to impose chemically induced stress by affecting functions related to maintenance energy requirements. Effects on basal metabolic rate (BMR) have been suggested to be, in part, mediated through interactions with the thyroid hormones (THs). We investigated the relationships between plasma concentrations of major organochlorines, PBDEs, hydroxylated (OH)- and methoxylated (MeO)-PBDEs and OH-PCBs, circulating TH levels and BMR in breeding glaucous gulls (Larus hyperboreus) from the Norwegian Arctic. Negative associations were found between BMR and concentrations of sigma PCB, Sigma DDT and particularly Sigma chlordane, which combined made up 91% of the total contaminant burden. Levels of THs (thyroxine and triiodothyronine) were not associated significantly with variation of BMR or concentrations of any of the compounds determined. The present study suggests that BMR may be altered in glaucous gulls exposed to high loadings of persistent contaminants in the Norwegian Arctic environment. 相似文献
593.
594.
Jonathan Wright 《Behavioral ecology and sociobiology》1998,42(6):423-429
Despite the success of kin selection in explaining helping-at-the-nest among communally breeding birds, we know almost nothing
about how helpers regulate their chick-feeding effort. This is especially interesting given how much we now know about parental
provisioning `rules-of-thumb' and the evolution of chick begging as an honest signal of `need'. This study explores the provisioning
rules of helpers and parents in Arabian babblers (Turdoides squamiceps), using tape play-backs to supplement chick-begging signals and increase apparent brood demand. In all eight groups tested,
both helpers and parents fed older, noisier broods at higher rates. Total provisioning rates to nests increased during begging
play-back days compared to control days. Absolute provisioning rates by helpers and the scale of their responses to play-backs
were statistically indistinguishable from those of parents. In both helpers and parents, increases in nest visits during play-backs
were associated with reductions in foraging distance from the nest and increases in size of prey delivered. Older birds of
both sexes delivered slightly larger prey items, possibly reflecting differences in foraging ability due to experience. These
results are consistent with the idea that, like the parents, helpers-at-the-nest in Arabian babblers provision nestlings as
part of a strategy of investment, irrespective of helper age, dominance status or sex. In this species, high relatedness within
groups may provide parents and helpers with similar kin-selected fitness benefits, although the mutualistic advantages to
helpers from simply augmenting group sizes cannot be ruled out.
Received: 17 June 1997 / Accepted after revision: 28 February 1998 相似文献
595.
Martin JW Asher BJ Beesoon S Benskin JP Ross MS 《Journal of environmental monitoring : JEM》2010,12(11):1979-2004
The extent to which perfluorooctanesulfonate precursors (PreFOS) play a role in human or environmental exposure to perfluorooctanesulfonate (PFOS) is not well characterized. The diversity of manufactured PreFOS and its degradation products (e.g. C(8)F(17)SO(2)R and C(8)F(17)SO(2)NR'R', where R is H or F, and R' and R' are various) has made it difficult to track their fate. Temporal trends of PFOS in both humans and wildlife are discrepant, thus it is difficult to predict future exposure, and hypotheses about the role of PreFOS have been raised. Although abiotic degradation of commercially important PreFOS materials requires further research, current data suggest that the yield of PFOS is negligible or minor. On the other hand, in vivo biotransformation of PreFOS yields PFOS as the major metabolite, and >32% yields have been observed. In Canadians, exposure to PreFOS was equivalent or greater than direct PFOS exposure prior to 2002. In most ocean water, PFOS is dominant to PreFOS, but in the oceans east of Greenland there may be more PreFOS than PFOS, consistent with the fact that whales and humans in this region also show evidence of substantial PreFOS exposure. Quantitative assessments of PFOS body-burdens coming from PreFOS are complicated by the fact that PreFOS partitions to the cellular fraction of blood, thus biomonitoring in serum under predicts PreFOS relative to PFOS. Many unknowns exist that prevent accurate modelling, thus analytical methods that can distinguish directly manufactured PFOS, from PFOS that has been biotransformed from PreFOS, should be applied in future human and environmental monitoring. Two new source tracking principles are presented and applied to human serum. 相似文献
596.
Autoclave decomposition method for metals in soils and sediments 总被引:1,自引:0,他引:1
Navarrete-López M Jonathan MP Rodríguez-Espinosa PF Salgado-Galeana JA 《Environmental monitoring and assessment》2012,184(4):2285-2293
Leaching of partially leached metals (Fe, Mn, Cd, Co, Cu, Ni, Pb, and Zn) was done using autoclave technique which was modified
based on EPA 3051A digestion technique. The autoclave method was developed as an alternative to the regular digestion procedure
passed the safety norms for partial extraction of metals in polytetrafluoroethylene (PFA vessel) with a low constant temperature
(119.5° ± 1.5°C) and the recovery of elements were also precise. The autoclave method was also validated using two Standard
Reference Materials (SRMs: Loam Soil B and Loam Soil D) and the recoveries were equally superior to the traditionally established
digestion methods. Application of the autoclave was samples from different natural environments (beach, mangrove, river, and
city soil) to reproduce the recovery of elements during subsequent analysis. 相似文献
597.
Alice A. Han Emily B. Fabyanic Julie V. Miller Maren S. Prediger Nicole Prince Julia A. Mouch Jonathan Boyd 《Environmental monitoring and assessment》2017,189(4):190
Thousands of gallons of industrial chemicals, crude 4-methylcyclohexanemethanol (MCHM) and propylene glycol phenyl ether (PPh), leaked from industrial tanks into the Elk River in Charleston, West Virginia, USA, on January 9, 2014. A considerable number of people were reported to exhibit symptoms of chemical exposure and an estimated 300,000 residents were advised not to use or drink tap water. At the time of the spill, the existing toxicological data of the chemicals were limited for a full evaluation of the health risks, resulting in concern among those in the impacted regions. In this preliminary study, we assessed cell viability and plasma membrane degradation following a 24-h exposure to varying concentrations (0–1000 μM) of the two compounds, alone and in combination. Evaluation of different cell lines, HEK-293 (kidney), HepG2 (liver), H9c2 (heart), and GT1-7 (brain), provided insight regarding altered cellular responses in varying organ systems. Single exposure to MCHM or PPh did not affect cell viability, except at doses much higher than the estimated exposure levels. Certain co-exposures significantly reduced metabolic activity and increased plasma membrane degradation in GT1-7, HepG2, and H9c2 cells. These findings highlight the importance of examining co-exposures to fully understand the potential toxic effects. 相似文献
598.
D'Ambrosio JL Williams LR Witter JD Ward A 《Environmental monitoring and assessment》2009,148(1-4):325-341
In this paper, we evaluate relationships between in-stream habitat, water chemistry, spatial distribution within a predominantly agricultural Midwestern watershed and geomorphic features and fish assemblage attributes and abundances. Our specific objectives were to: (1) identify and quantify key environmental variables at reach and system wide (watershed) scales; and (2) evaluate the relative influence of those environmental factors in structuring and explaining fish assemblage attributes at reach scales to help prioritize stream monitoring efforts and better incorporate all factors that influence aquatic biology in watershed management programs. The original combined data set consisted of 31 variables measured at 32 sites, which was reduced to 9 variables through correlation and linear regression analysis: stream order, percent wooded riparian zone, drainage area, in-stream cover quality, substrate quality, gradient, cross-sectional area, width of the flood prone area, and average substrate size. Canonical correspondence analysis (CCA) and variance partitioning were used to relate environmental variables to fish species abundance and assemblage attributes. Fish assemblages and abundances were explained best by stream size, gradient, substrate size and quality, and percent wooded riparian zone. Further data are needed to investigate why water chemistry variables had insignificant relationships with IBI scores. Results suggest that more quantifiable variables and consideration of spatial location of a stream reach within a watershed system should be standard data incorporated into stream monitoring programs to identify impairments that, while biologically limiting, are not fully captured or elucidated using current bioassessment methods. 相似文献
599.
Regional Environmental Change - Proactively managing disaster risk in the absence of an event is the result of the responsible organization or institution’s political will. This paper is a... 相似文献
600.
The Impact of Projected Climate Change Scenarios on Nitrogen Yield at a Regional Scale for the Contiguous United States
下载免费PDF全文
![点击此处可从《Journal of the American Water Resources Association》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Md Jahangir Alam Jonathan L. Goodall Benjamin D. Bowes Evan H. Girvetz 《Journal of the American Water Resources Association》2017,53(4):854-870
Improved understanding of the potential regional impacts of projected climatic changes on nitrogen yield is needed to inform water resources management throughout the United States (U.S.). The objective of this research is to look broadly at watersheds in the contiguous U.S. to assess the potential regional impact of changes in precipitation (P) and air temperature (T) on nitrogen yield. The SPAtially Referenced Regression On Watershed attributes model and downscaled P and T outputs from 14 general circulation models were used to explore impacts on nitrogen yield. Results of the analysis suggest that projected changes in P and T will decrease nitrogen yield for the majority of the contiguous U.S., including the watersheds of the Chesapeake Bay and Gulf of Mexico. Some regions, however, such as the Pacific Northwest and Northern California, are projected to face climatic conditions that, according to the model results, may increase nitrogen yield. Combining the projections of climate‐driven changes in nitrogen yield with projected changes in watershed nitrogen inputs could help water resource managers develop regionally specific, long‐term strategies to mitigate nitrogen pollution. 相似文献