全文获取类型
收费全文 | 1265篇 |
免费 | 32篇 |
国内免费 | 11篇 |
专业分类
安全科学 | 76篇 |
废物处理 | 40篇 |
环保管理 | 325篇 |
综合类 | 147篇 |
基础理论 | 344篇 |
环境理论 | 3篇 |
污染及防治 | 229篇 |
评价与监测 | 92篇 |
社会与环境 | 46篇 |
灾害及防治 | 6篇 |
出版年
2023年 | 13篇 |
2022年 | 13篇 |
2021年 | 17篇 |
2020年 | 17篇 |
2019年 | 15篇 |
2018年 | 27篇 |
2017年 | 42篇 |
2016年 | 45篇 |
2015年 | 31篇 |
2014年 | 40篇 |
2013年 | 78篇 |
2012年 | 56篇 |
2011年 | 76篇 |
2010年 | 58篇 |
2009年 | 46篇 |
2008年 | 74篇 |
2007年 | 74篇 |
2006年 | 68篇 |
2005年 | 46篇 |
2004年 | 50篇 |
2003年 | 50篇 |
2002年 | 43篇 |
2001年 | 25篇 |
2000年 | 16篇 |
1999年 | 22篇 |
1998年 | 20篇 |
1997年 | 17篇 |
1996年 | 23篇 |
1995年 | 28篇 |
1994年 | 15篇 |
1993年 | 14篇 |
1992年 | 12篇 |
1991年 | 10篇 |
1990年 | 7篇 |
1989年 | 8篇 |
1988年 | 10篇 |
1987年 | 9篇 |
1986年 | 5篇 |
1985年 | 6篇 |
1984年 | 11篇 |
1983年 | 6篇 |
1982年 | 7篇 |
1981年 | 6篇 |
1978年 | 5篇 |
1975年 | 3篇 |
1974年 | 4篇 |
1972年 | 3篇 |
1963年 | 4篇 |
1954年 | 4篇 |
1938年 | 3篇 |
排序方式: 共有1308条查询结果,搜索用时 15 毫秒
51.
52.
Coupling of the Water Cycle with Patterns of Urban Growth in the Baltimore Metropolitan Region,United States 下载免费PDF全文
Aditi S. Bhaskar Claire Jantz Claire Welty Scott A. Drzyzga Andrew J. Miller 《Journal of the American Water Resources Association》2016,52(6):1509-1523
Regional municipal water plans typically do not recognize complex coupling patterns or that increased withdrawals in one location can result in changes in water availability in others. We investigated the interaction between urban growth and water availability in the Baltimore metropolitan region where urban growth has occurred beyond the reaches of municipal water systems into areas that rely on wells in low‐productivity Piedmont aquifers. We used the urban growth model SLEUTH and the hydrologic model ParFlow.CLM to evaluate this interaction with urban growth scenarios in 2007 and 2030. We found decreasing groundwater availability outside of the municipal water service area. Within the municipal service area we found zones of increasing storage resulting from increased urban growth, where reduced vegetation cover dominated the effect of urbanization on the hydrologic cycle. We also found areas of decreasing storage, where expanding impervious surfaces played a larger role. Although the magnitude of urban growth and change in water availability for the simulation period were generally small, there was considerable spatial heterogeneity of changes in subsurface storage. This suggests that there are locally concentrated areas of groundwater sensitivity to urban growth where water shortages could occur or where drying up of headwater streams would be more likely. The simulation approach presented here could be used to identify early warning indicators of future risk. 相似文献
53.
Research and application of method of oxygen isotope of inorganic phosphate in Beijing agricultural soils 总被引:1,自引:0,他引:1
Liyan Tian Qingjun Guo Yongguan Zhu Huijun He Yunchao Lang Jian Hu Han Zhang Rongfei Wei Xiaokun Han Marc Peters Junxing Yang 《Environmental science and pollution research international》2016,23(23):23406-23414
Phosphorus (P) in agricultural ecosystems is an essential and limited element for plants and microorganisms. However, environmental problems caused by P accumulation as well as by P loss have become more and more serious. Oxygen isotopes of phosphate can trace the sources, migration, and transformation of P in agricultural soils. In order to use the isotopes of phosphate oxygen, appropriate extraction and purification methods for inorganic phosphate from soils are necessary. Here, we combined two different methods to analyze the oxygen isotopic composition of inorganic phosphate (δ18OP) from chemical fertilizers and different fractions (Milli-Q water, 0.5 mol L?1 NaHCO3 (pH = 8.5), 0.1 mol L?1 NaOH and 1 mol L?1 HCl) of agricultural soils from the Beijing area. The δ18OP results of the water extracts and NaHCO3 extracts in most samples were close to the calculated equilibrium value. These phenomena can be explained by rapid P cycling in soils and the influence of chemical fertilizers. The δ18OP value of the water extracts and NaHCO3 extracts in some soil samples below the equilibrium value may be caused by the hydrolysis of organic P fractions mediated by extracellular enzymes. The δ18OP values of the NaOH extracts were above the calculated equilibrium value reflecting the balance state between microbial uptake of phosphate and the release of intracellular phosphate back to the soil. The HCl extracts with the lowest δ18OP values and highest phosphate concentrations indicated that the HCl fraction was affected by microbial activity. Hence, these δ18Op values likely reflected the oxygen isotopic values of the parent materials. The results suggested that phosphate oxygen isotope analyses could be an effective tool in order to trace phosphate sources, transformation processes, and its utilization by microorganisms in agricultural soils. 相似文献
54.
Climate change generally requires species to migrate northward or to higher elevation to maintain constant climate conditions, but migration requirement and migration capacity of individual species can vary greatly. Individual populations of species occupy different positions in the landscape that determine their required range shift to maintain similar climate, and likewise the migration capacity depends on habitat connectivity. Here, we demonstrate an approach to quantifying species vulnerabilities to climate change for 419 rare vascular plants in Alberta, Canada, based on a multivariate velocity of climate change metric, local habitat fragmentation, and migration capacity. Climate change velocities indicated that future migration requirements ranged from 1 to 5 km/year in topographically complex landscapes, such as the Alberta Foothills and Rocky Mountains. In contrast, migration requirements to maintain constant climate in relatively flat Boreal Plains, Parkland, and Grassland ranged from 4 to 8 km/year. Habitat fragmentation was also highest in these flat regions, particularly the Parkland Natural Region. Of the 419 rare vascular plants assessed, 36 were globally threatened (G1–G3 ranking). Three globally threatened species were ranked as extremely vulnerable and five species as highly vulnerable to the interactions among climate change velocity, habitat fragmentation, and migration capacity. Incorporating dispersal characteristics and habitat fragmentation with local patterns in climate change velocity improves the assessment of climate change threats to species and may be applied to guide monitoring efforts or conservation actions. 相似文献
55.
Scott Newey Paul Davidson Sajid Nazir Gorry Fairhurst Fabio Verdicchio R. Justin Irvine René van der Wal 《Ambio》2015,44(4):624-635
The availability of affordable ‘recreational’ camera traps has dramatically increased over the last decade. We present survey results which show that many conservation practitioners use cheaper ‘recreational’ units for research rather than more expensive ‘professional’ equipment. We present our perspective of using two popular models of ‘recreational’ camera trap for ecological field-based studies. The models used (for >2 years) presented us with a range of practical problems at all stages of their use including deployment, operation, and data management, which collectively crippled data collection and limited opportunities for quantification of key issues arising. Our experiences demonstrate that prospective users need to have a sufficient understanding of the limitations camera trap technology poses, dimensions we communicate here. While the merits of different camera traps will be study specific, the performance of more expensive ‘professional’ models may prove more cost-effective in the long-term when using camera traps for research. 相似文献
56.
The extensive literature on environmental justice has, by now, well defined the essential ingredients of cumulative risk,
namely, incompatible land uses and vulnerability. Most problematic is the case when risk is produced by a large aggregation
of small sources of air toxics. In this article, we test these notions in an area of Southern California, Southeast Los Angeles
(SELA), which has come to be known as Asthmatown. Developing a rapid risk mapping protocol, we scan the neighborhood for small
potential sources of air toxics and find, literally, hundreds of small point sources within a 2-mile radius, interspersed
with residences. We also map the estimated cancer risks and noncancer hazard indices across the landscape. We find that, indeed,
such large aggregations of even small, nondominant sources of air toxics can produce markedly elevated levels of risk. In
this study, the risk profiles show additional cancer risks of up to 800 in a million and noncancer hazard indices of up to
200 in SELA due to the agglomeration of small point sources. This is significant (for example, estimates of the average regional
point-source-related cancer risk range from 125 to 200 in a million). Most importantly, if we were to talk about the risk
contour as if they were geological structures, we would observe not only a handful of distinct peaks, but a general “mountain
range” running all throughout the study area, which underscores the ubiquity of risk in SELA. Just as cumulative risk has
deeply embedded itself into the fabric of the place, so, too, must intervention seek to embed strategies into the institutions
and practices of SELA. This has implications for advocacy, as seen in a recently initiated participatory action research project
aimed at building health research capacities into the community in keeping with an ethic of care. 相似文献
57.
Colten Craig E. Simms Jessica R. Z. Grismore Audrey A. Hemmerling Scott A. 《Regional Environmental Change》2018,18(2):371-383
Regional Environmental Change - Louisiana faces extensive coastal land loss which threatens the livelihoods of marginalized populations. These groups have endured extreme disruptive events in the... 相似文献
58.
Dominic Bekoe Bo Zhang Matthew Scott Todd Abolghasem Shahbazi 《Journal of environmental science and health. Part. B》2018,53(2):145-151
Aerobic treatment of swine manure was coupled with anaerobic digestion and microalgal cultivation. A 14-day aerobic treatment reduced the total solid content of swine manure by >15%. Ammonia and carbon dioxide were stripped by the air supplied, and this off-gas was further used to aerate the culture of Chlorella vulgaris. The microalgal growth rates in Bristol medium and the wastewater with the off-gas increased from 0.08 to 0.22 g/L/d and from 0.15 to 0.24 g/L/d, respectively. Meanwhile, the aerobically treated swine manure showed a higher methane yield during anaerobic digestion. The experimental results were used to establish a demonstration unit consisting of a 100 L composter, a 200 L anaerobic digester, a 60 L tubular photobioreactor, and a 300 L micro-open raceway pond. 相似文献
59.
Used engine oils contain metals, which upon entering soils may pose risks to human health or the environment. In this study, previously published concentrations of 23 metals in 213 used engine oil samples from the early 1970s to the mid-1990s are statistically evaluated. Neat (100%) used engine oils were found to contain relatively high concentrations of lead, calcium, and zinc, attributable to piston blow-by of leaded gasoline, calcium salt detergent additives, and zinc-bearing anti-corrosion/anti-oxidation additives, respectively. Wear metal concentrations were lower. The lead concentration in used engine oils in the U.S. declined between the 1970s and early 1990s, potentially providing a basis to constrain the “age” of used engine oil(s) in soils. The concentrations of 23 metals in used engine oils were compared to soil risk benchmarks in 15 representative jurisdictions in the U.S., Canada, Australia, and Europe. The maximum concentrations in neat (100%) used engine oil of eight metals – Be, Co, Fe, Mn, Ni, Se, Ag, and Ti – were lower than their collective minimum benchmarks in soils for the jurisdictions surveyed, indicating their concentrations in soils could not be reasonably expected to exceed any soil benchmarks. Nine metals (As, Ba, Cd, Cr, Cu, Pb, Sn, V and Zn), but particularly arsenic, cadmium, lead, tin, and zinc, were identified as potential contaminants of concern (PCOC) for soils from locations impacted with used engine oils, owing to their higher median concentrations (i.e., 2.5, 1.4, 1038, 5.0, and 922 mg/kg in oil, respectively) relative to most soil benchmarks. Site-specific benchmarks and metal concentrations at reasonable oil in soil concentrations require consideration when developing the suite of PCOC metal analytes for conducting site assessments of soils impacted by used engine oil. 相似文献
60.
Mahiba Shoeib Penny Vlahos Tom Harner Andrew Peters Margaret Graustein Julie Narayan 《Atmospheric environment (Oxford, England : 1994)》2010,44(24):2887-2893
High volume air sampling in Bermuda, Sable Island (Nova Scotia) and along a cruise track from the Gulf of Mexico to northeast coast of the USA, was carried out to assess air concentrations, particle-gas partitioning and transport of polyfluorinated chemicals (PFCs) in this region. Samples were collected in the summer of 2007. Targeted compounds included the neutral PFCs: fluorotelomer alcohols (FTOHs), perfluoroalkyl sulfonamides (FOSAs) and perfluoroalkyl sulfonamido ethanols (FOSEs).Among the FTOHs, 8:2 FTOH was dominant in all samples. Sum of the concentration of FTOHs (gas+particle phase) were higher in Bermuda (mean, 34 pg m?3) compared to Sable Island (mean, 16 pg m?3). In cruise samples, sum of FTOHs were highly variable (mean, 81 pg m?3) reflecting contributions from land-based sources in the northeast USA with concentrations reaching as high as 156 pg m?3.Among the FOSAs and FOSEs, MeFOSE was dominant in all samples. In Bermuda, levels of MeFOSE were exceptionally high (mean, 62 pg m?3), exceeding the FTOHs. Sable Island samples also exhibited the dominance of MeFOSE but at a lower concentration (mean, 15 pg m?3). MeFOSE air concentrations (pg m?3) in cruise samples ranged from 1.6 to 73 and were not linked to land-based sources. In fact high concentrations of MeFOSE observed in Bermuda were associated with air masses that originated over the Atlantic Ocean.The partitioning to particles for 8:2 FTOH, 10:2 FTOH, MeFOSE and EtFOSE ranged from as high as 15 to 42% for cruise samples to 0.9 to 14% in Bermuda. This study provides key information for validating and developing partitioning and transport models for the PFCs. 相似文献