全文获取类型
收费全文 | 2805篇 |
免费 | 69篇 |
国内免费 | 25篇 |
专业分类
安全科学 | 107篇 |
废物处理 | 118篇 |
环保管理 | 590篇 |
综合类 | 245篇 |
基础理论 | 847篇 |
环境理论 | 5篇 |
污染及防治 | 618篇 |
评价与监测 | 189篇 |
社会与环境 | 150篇 |
灾害及防治 | 30篇 |
出版年
2023年 | 16篇 |
2022年 | 34篇 |
2021年 | 42篇 |
2020年 | 39篇 |
2019年 | 41篇 |
2018年 | 63篇 |
2017年 | 60篇 |
2016年 | 95篇 |
2015年 | 80篇 |
2014年 | 82篇 |
2013年 | 253篇 |
2012年 | 104篇 |
2011年 | 187篇 |
2010年 | 116篇 |
2009年 | 144篇 |
2008年 | 157篇 |
2007年 | 162篇 |
2006年 | 131篇 |
2005年 | 106篇 |
2004年 | 92篇 |
2003年 | 94篇 |
2002年 | 78篇 |
2001年 | 54篇 |
2000年 | 41篇 |
1999年 | 45篇 |
1998年 | 33篇 |
1997年 | 34篇 |
1996年 | 38篇 |
1995年 | 46篇 |
1994年 | 37篇 |
1993年 | 33篇 |
1992年 | 28篇 |
1991年 | 33篇 |
1990年 | 23篇 |
1989年 | 22篇 |
1988年 | 15篇 |
1987年 | 19篇 |
1986年 | 20篇 |
1985年 | 13篇 |
1984年 | 28篇 |
1983年 | 14篇 |
1982年 | 20篇 |
1981年 | 15篇 |
1980年 | 16篇 |
1979年 | 10篇 |
1978年 | 10篇 |
1977年 | 13篇 |
1975年 | 12篇 |
1974年 | 8篇 |
1971年 | 7篇 |
排序方式: 共有2899条查询结果,搜索用时 15 毫秒
921.
922.
923.
Long Ngo Louise M. Ryan Maura Mezzetti Frédéric Y. Bois Thomas J. Smith 《Environmental and Ecological Statistics》2011,18(1):131-146
In a study of 133 volunteer subjects, demographic, physiologic and pharmacokinetic data through exposure to 1,3-Butadiene
(BD) were collected in order to estimate the percentage of BD concentration metabolized at steady state, and to determine
whether this percentage varies across gender, racial, and age groups. During the 20 min of continuous exposure to 2 parts
per million (ppm) of BD, five measurements of exhaled concentration were made on each subject. In the following 40 min washout
period, another five measurements were collected. A Bayesian hierarchical compartmental physiologically-based pharmacokinetic
model (PKPB) was used. Using prior information on the model parameters, Markov Chain Monte Carlo (MCMC) simulation was conducted
to obtain posterior distributions. The overall estimate of the mean percent of BD metabolized at steady state was 12.7% (95%
credible interval: 7.7–17.8%). There was no significant difference in gender with males having a mean of 13.5%, and females
12.3%. Among the racial groups, Hispanic (13.9%), White (13.0%), Asian (12.1%), and Black (10.9%), the significant difference
came from the difference between Black and Hispanic with a 95% credible interval from −5.63 to −0.30%. Those older than 30 years
had a mean of 12.2% versus 12.9% for the younger group; although this was not a statistically significant difference. Given
a constant inhalation input of 2 ppm, at steady state, the overall mean exhaled concentration was estimated to be 1.75ppm
(95% credible interval: 1.64–1.84). An equivalent parameter, first-order metabolic rate constant, was also estimated and found
to be consistent with the percent of BD metabolized at steady state across gender, race, and age strata. 相似文献
924.
In the United Kingdom, the use of TBT-based anti-fouling paints on small vessels was banned in 1987, and a biological study
of the Crouch Estuary, a yachting centre on the south-eastern coast of the UK, was conducted in order to determine the ecological
improvements resulting from this legislation. We present the changes in the macro-infaunal communities along the estuary in
relation to declining TBT concentrations between 1987 and 2005. Although the major changes in response to the ban were observed
within the first 3 years (primarily an increase in the number of crustacean taxa and a shift in community structure), with
changes still apparent between three and 5 years, the temporal duration of this study allowed the rapidity of the response
to be truly determined. 相似文献
925.
Sedillo JL Quintana A Souza K Oshima KH Smith GB 《Journal of environmental monitoring : JEM》2008,10(6):718-723
The foundational idea for this project is that household faucet-mounted water filters may be used as bioforensic sampling devices to detect the extent of a potential bioagent release in domestic water supplies. An optimized eluent solution was determined experimentally by quantifying recoveries of microorganisms from point-of-use (POU) drinking water filters. The optimized extraction protocol was then used in mock bioagent release experiments to determine the feasibility of POU filters as bioforensic sampling devices. Bacillus atrophaeus spores, Escherichia coli and PP7 virus were exposed to filters and the number of attached organisms was determined by enumerating the unattached organisms on selective agar media. Subsequently, the filters were eluted and the percent of extracted organisms was determined based on the number of attached organisms. Two popular brands of carbon block filters retained 92%-99% of representative virus, spore and vegetative bacteria. In back-flush elutions of single filters, the most efficient eluent was identified as a combination of 1% peptone and 1% Tween-80, and extraction recovered 25.4% (+/-17.5%) of attached E. coli, 20.4% (+/-3.6%) of B. atrophaeus spores, and 9.4% (+/-5.2%) of PP7 virions (+/- standard deviations). In bioagent release studies in which filters were challenged with 100 agents mL(-1), greater than 99% of the spores were retained by the filters, and the percent of attached spores that were recovered ranged from 10.4% at day 0 to 4.3% five days after the release event (averaged from five separate experiments). In contrast, E. coli, Salmonella typhimurium and PP7 virus were rapidly inactivated in the chlorinated tap water, indicating their improbable survival in chlorinated water supplies. It is therefore concluded that household water filters can be used as microbial sampling devices for bioforensic applications in the event of a bioagent release in domestic drinking water supplies. 相似文献
926.
Dearing JA Bullock S Costanza R Dawson TP Edwards ME Poppy GM Smith GM 《Environmental management》2012,49(4):767-775
The ‘Perfect Storm’ metaphor describes a combination of events that causes a surprising or dramatic impact. It lends an evolutionary
perspective to how social-ecological interactions change. Thus, we argue that an improved understanding of how social-ecological
systems have evolved up to the present is necessary for the modelling, understanding and anticipation of current and future
social-ecological systems. Here we consider the implications of an evolutionary perspective for designing research approaches.
One desirable approach is the creation of multi-decadal records produced by integrating palaeoenvironmental, instrument and
documentary sources at multiple spatial scales. We also consider the potential for improved analytical and modelling approaches
by developing system dynamical, cellular and agent-based models, observing complex behaviour in social-ecological systems
against which to test systems dynamical theory, and drawing better lessons from history. Alongside these is the need to find
more appropriate ways to communicate complex systems, risk and uncertainty to the public and to policy-makers. 相似文献
927.
Spatial and temporal drivers of zoonotic pathogen contamination of an agricultural watershed 总被引:1,自引:0,他引:1
Jokinen CC Edge TA Koning W Laing CR Lapen DR Miller J Mutschall S Scott A Taboada EN Thomas JE Topp E Wilkes G Gannon VP 《Journal of environmental quality》2012,41(1):242-252
In regions where animal agriculture is prominent, such as southern Alberta, higher rates of gastrointestinal illness have been reported when compared with nonagricultural regions. This difference in the rate of illness is thought to be a result of increased zoonotic pathogen exposure through environmental sources such as water. In this study, temporal and spatial factors associated with bacterial pathogen contamination of the Oldman River, which transverses this region, were analyzed using classification and regression tree analysis. Significantly higher levels of fecal indicators; more frequent isolations of Campylobacter spp., Escherichia coli O157:H7, and Salmonella enterica spp.; and higher rates of detection of pig-specific Bacteroides markers occurred at downstream sites than at upstream sites, suggesting additive stream inputs. Fecal indicator densities were also significantly higher when any one of these three bacterial pathogens was present and where there were higher total animal manure units; however, occasionally pathogens were present when fecal indicator levels were low or undetectable. Overall, Salmonella spp., Campylobacter spp., and E. coli O157:H7 presence was associated with season, animal manure units, and total rainfall on the day of sampling and 3 d in advance of sampling. Several of the environmental variables analyzed in this study appear to influence pathogen prevalence and therefore may be useful in predicting water quality and safety and in the improvement of watershed management practices in this and other agricultural regions. 相似文献
928.
The objective of this study was to evaluate which macroinvertebrate and deposited sediment metrics are best for determining effects of excessive sedimentation on stream integrity. Fifteen instream sediment metrics, with the strongest relationship to land cover, were compared to riffle macroinvertebrate metrics in streams ranging across a gradient of land disturbance. Six deposited sediment metrics were strongly related to the relative abundance of Ephemeroptera, Plecoptera and Trichoptera and six were strongly related to the modified family biotic index (MFBI). Few functional feeding groups and habit groups were significantly related to deposited sediment, and this may be related to the focus on riffle, rather than reach-wide macroinvertebrates, as reach-wide sediment metrics were more closely related to human land use. Our results suggest that the coarse-level deposited sediment metric, visual estimate of fines, and the coarse-level biological index, MFBI, may be useful in biomonitoring efforts aimed at determining the impact of anthropogenic sedimentation on stream biotic integrity. 相似文献
929.
The United States has lost about half its wetland acreage since European settlement, and the effectiveness of current wetland mitigation policies is often questioned. In most states, federal wetland laws are overseen by the U.S. Army Corps of Engineers, but Michigan administers these laws through the state's Department of Environmental Quality (MDEQ). Our research provides insight into the effectiveness of the state's implementation of these laws. We examined wetland mitigation permit files issued in Michigan's Upper Peninsula between 2003 and 2006 to assess compliance with key MDEQ policies. Forty-six percent of files were out of compliance with monitoring report requirements, and forty-nine percent lacked required conservation easement documents. We also conducted site assessments of select compensatory wetland projects to determine compliance with MDEQ invasive plant species performance standards. Fifty-five percent were out of compliance. We found no relationship between invasive species noncompliance and past site monitoring, age of mitigation site, or proximity to roads. However, we found wetland restoration projects far more likely to be compliant with performance standards than wetland creation projects. We suggest policy changes and agency actions that could increase compliance with wetland restoration and mitigation goals. 相似文献
930.
Pete Campana John Knox Andrew Grundstein John Dowd 《Journal of the American Water Resources Association》2012,48(2):379-390
Campana, Pete, John Knox, Andrew Grundstein, and John Dowd, 2012. The 2007‐2009 Drought in Athens, Georgia, United States: A Climatological Analysis and an Assessment of Future Water Availability. Journal of the American Water Resources Association (JAWRA) 48(2): 379‐390. DOI: 10.1111/j.1752‐1688.2011.00619.x Abstract: Population growth and development in many regions of the world increase the demand for water and vulnerability to water shortages. Our research provides a case study of how population growth can augment the severity of a drought. During 2007‐2009, a drought event that caused extreme societal impacts occurred in the Athens, Georgia region (defined as Clarke, Barrow, Oconee, and Jackson counties). An examination of drought indices and precipitation records indicates that conditions were severe, but not worse than during the 1925‐1927, 1954‐1956, and 1985‐1987 drought events. A drought of similar length to the 2007‐2009 drought would be expected to occur approximately every 25 years. Streamflow analysis shows that discharge levels in area streams were at a record low during 2007 before water restrictions were implemented, because of greater water usage caused by recent population increases. These population increases, combined with a lack of water conservation, led to severe water shortages in the Athens region during late 2007. Only after per capita usage decreased did water resources last despite continuing drought conditions through 2009. Retaining mitigation strategies and withdrawal levels such as seen during the height of the drought will be an essential strategy to prevent water shortages during future extreme drought events. The key mitigation strategy, independent local action to restrict water use in advance of state‐level restrictions, is now prohibited by Georgia State Law. 相似文献