全文获取类型
收费全文 | 884篇 |
免费 | 13篇 |
国内免费 | 9篇 |
专业分类
安全科学 | 38篇 |
废物处理 | 24篇 |
环保管理 | 213篇 |
综合类 | 86篇 |
基础理论 | 253篇 |
环境理论 | 2篇 |
污染及防治 | 154篇 |
评价与监测 | 68篇 |
社会与环境 | 52篇 |
灾害及防治 | 16篇 |
出版年
2022年 | 7篇 |
2021年 | 8篇 |
2020年 | 11篇 |
2019年 | 11篇 |
2018年 | 26篇 |
2017年 | 18篇 |
2016年 | 34篇 |
2015年 | 19篇 |
2014年 | 23篇 |
2013年 | 61篇 |
2012年 | 29篇 |
2011年 | 51篇 |
2010年 | 32篇 |
2009年 | 47篇 |
2008年 | 42篇 |
2007年 | 36篇 |
2006年 | 37篇 |
2005年 | 32篇 |
2004年 | 24篇 |
2003年 | 23篇 |
2002年 | 30篇 |
2001年 | 21篇 |
2000年 | 23篇 |
1999年 | 14篇 |
1998年 | 15篇 |
1997年 | 9篇 |
1996年 | 16篇 |
1995年 | 20篇 |
1994年 | 20篇 |
1993年 | 16篇 |
1992年 | 10篇 |
1991年 | 8篇 |
1990年 | 10篇 |
1989年 | 6篇 |
1988年 | 11篇 |
1987年 | 9篇 |
1986年 | 4篇 |
1985年 | 11篇 |
1984年 | 12篇 |
1983年 | 14篇 |
1982年 | 9篇 |
1981年 | 6篇 |
1980年 | 4篇 |
1979年 | 10篇 |
1977年 | 3篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1972年 | 4篇 |
1968年 | 2篇 |
1967年 | 2篇 |
排序方式: 共有906条查询结果,搜索用时 15 毫秒
701.
Susan J. Van De Meene Rebekah R. Brown 《Journal of the American Water Resources Association》2009,45(6):1448-1464
van de Meene, Susan J. and Rebekah R. Brown, 2009. Delving into the “Institutional Black Box”: Revealing the Attributes of Sustainable Urban Water Management Regimes. Journal of the American Water Resources Association (JAWRA) 45(6):1448‐1464. Abstract: This paper is based on the proposition that the transition to sustainable urban water management has been hampered by the lack of insight into attributes of a sustainable urban water regime. Significant progress has been made in developing technical solutions to advance urban water practice, however it is the co‐evolution of the socio‐institutional and technical systems that enable a system‐wide transition. A systematic analysis of 81 empirical studies across a range of practice areas was undertaken to construct a schema of the sustainable urban water regime attributes. Attributes were identified and analyzed using a framework of nested management regime spheres: the administrative and regulatory system, inter‐organizational, intra‐organizational, and human resources spheres. The regime is likely to involve significant stakeholder involvement, collaborative inter‐organizational relationships, flexible and adaptive organizational cultures, and motivated and engaging employees. Comparison of the constructed sustainable and traditional regime attributes reveals that to realize sustainable urban water management in practice a substantial shift in governance is required. This difference emphasizes the critical need for explicitly supported strategies targeted at developing each management regime sphere to further enable change toward sustainable urban water management. 相似文献
702.
Han T Han YS Park CY Jun YS Kwon MJ Kang SH Brown MT 《Environmental pollution (Barking, Essex : 1987)》2008,153(3):699-705
A toxicity test using spore release of the aquatic green alga, Ulva, was developed and evaluated by assessing the toxicity of different organic and inorganic chemicals and elutriates of sewage or waste sludge. The toxic ranking of four metals was: Cu (EC50 of 0.040mgL(-1))>Cd (0.095mgL(-1))>Pb (0.489mgL(-1))>Zn (0.572mgL(-1)). The EC50 for TBTO ranged from 24 to 63microgL(-1). The most toxic VOC was formalin (EC50 of 0.788microlL(-1)) and the least toxic was acetone. Spore release was significantly inhibited in all elutriates; the greatest and least toxic effects were for industrial sewage (3.29%) and filtration bed (10.08%), respectively. The bioassay is simple, inexpensive and sensitive. The cosmopolitan distribution of Ulva means that the test would have a potential application worldwide. 相似文献
703.
704.
Data from 25 sites were used to evaluate associations between macroinvertebrate assemblages on large woody debris (snags) and environmental variables in the lower San Joaquin and Sacramento River drainages in California as part of the U.S. Geological Survey's National Water Quality Assessment Program. Samples were collected from 1993 to 1995 in the San Joaquin River drainage and in 1996 and 1997 in the Sacramento River drainage. Macroinvertebrate taxa were aggregated to the family (or higher) level of taxonomic organization, resulting in 39 taxa for analyses. Only the 31 most common taxa were used for two-way indicator species analysis (TWINSPAN) and canonical correspondence analysis (CCA). TWINSPAN analysis defined four groups of snag samples on the basis of macroinvertebrate assemblages. Analysis of variance identified differences in environmental and biotic characteristics among the groups. These results combined with the results of CCA indicated that mean dominant substrate type, gradient, specific conductance, water temperature, percentage of the basin in agricultural land use, percentage of the basin in combined agricultural and urban land uses, and elevation were important factors in explaining assemblage structure. Macroinvertebrate assemblages on snags may be useful in family level bioassessments of environmental conditions in valley floor habitats. 相似文献
705.
Brown RJ Yardley RE Muhunthan D Butterfield DM Williams M Woods PT Brown AS Goddard SL 《Environmental monitoring and assessment》2008,142(1-3):127-140
Ambient air quality has been an important issue for humans and the environment for hundreds of years. More recently, definitive links have been identified between pollutants and adverse effects on human health and on environmental sustainability. Of particular concern since the last quarter of the twentieth century has been the presence of toxic 'heavy metals' in ambient air. In order to measure the concentrations of pollutants, including 'heavy metals', in ambient air, to assess human and environmental exposure, comply with developing legislation, and assess newly introduced abatement strategies, the UK government established nationwide air quality measurement networks in the late 1970s. The nationwide measurement of 'heavy metals' in ambient air began in the late 1970s, and in 1980 was developed into several national networks, aimed at different metals and different emissions sources. These networks were rationalised into the current UK Heavy Metals Monitoring Network in 2003. The data produced by the current scientific operator of the Network, the National Physical Laboratory (NPL), in 2005, marked 25 years of ambient 'heavy metals' measurement in the UK at a nationwide level. This paper celebrates this milestone and provides a novel and critical examination of Network operations, measured concentration levels, and trends, over the last quarter of a century. 相似文献
706.
Tidal streams are ecologically important components of lotic network, and we identify dissolved oxygen (DO) depletion as a potentially important stressor in freshwater tidal streams of northern New Zealand. Other studies have examined temporal DO variability within rivers and we build on this by examining variability between streams as a basis for regional-scale predictors of risk for DO stress. Diel DO variability in these streams was driven by: (1) photosynthesis by aquatic plants and community respiration which produced DO maxima in the afternoon and minima early morning (range, 0.6-4.7 g/m(3)) as a product of the solar cycle and (2) tidal variability as a product of the lunar cycle, including saline intrusions with variable DO concentrations plus a small residual effect on freshwater DO for low-velocity streams. The lowest DO concentrations were observed during March (early autumn) when water temperatures and macrophyte biomass were high. Spatial comparisons indicated that low-gradient tidal streams were at greater risk of DO depletions harmful to aquatic life. Tidal influence was stronger in low-gradient streams, which typically drain more developed catchments, have lower reaeration potential and offer conditions more suitable for aquatic plant proliferation. Combined, these characteristics supported a simple method based on the extent of low-gradient channel for identifying coastal streams at risk of DO depletion. High-risk streams can then be targeted for riparian planting, nutrient limits and water allocation controls to reduce potential ecological stress. 相似文献
707.
Bergquist DC Heuberger D Sturmer LN Baker SM 《Environmental monitoring and assessment》2009,148(1-4):409-419
In 2000, Florida's fast-growing hard clam aquaculture industry became eligible for federal agricultural crop insurance through the US Department of Agriculture, but the responsibility for identifying the cause of mortality remained with the grower. Here we describe the continuous water quality monitoring system used to monitor hard clam aquaculture areas in Florida and show examples of the data collected with the system. Systems recording temperature, salinity, dissolved oxygen, water depth, turbidity and chlorophyll at 30 min intervals were installed at 10 aquaculture lease areas along Florida's Gulf and Atlantic coasts. Six of these systems sent data in real-time to a public website, and all 10 systems provided data for web-accessible archives. The systems documented environmental conditions that could negatively impact clam survival and productivity and identified biologically relevant water quality differences among clam aquaculture areas. Both the real-time and archived data were used widely by clam growers and nursery managers to make management decisions and in filing crop loss insurance claims. While the systems were labor and time intensive, we recommend adjustments that could reduce costs and staff time requirements. 相似文献
708.
Evaluating Genetic Diversity Associated with Propagation-Assisted Restoration of American Shad 总被引:3,自引:0,他引:3
B. L. Brown § T. P. Gunter † J. M. Waters ‡ and J. M. Epifanio 《Conservation biology》2000,14(1):294-303
Abstract: We investigated the conservation of genetic diversity during a restoration program for American shad ( Alosa sapidissima ) in Virginia ( U.S.A.). Restoration entailed capture of wild Pamunkey River shad broodstock followed by production and release of hatchery-reared fry to supplement the nearly extinct James River shad population. To assess the baseline genetic diversity of donor and recipient populations, we used five tri- and tetra-nucleotide microsatellite loci to test for genetic heterogeneity among yearly subsamples from both rivers and between early- and late-spawning shad from the donor population. Tests for allelic heterogeneity between James River and Pamunkey shad subsamples yielded no significant genetic differentiation (χ 2 = 14.72, p = 0.132 and χ 2 = 10.24, p = 0.440, respectively). We detected no significant genetic divergence between early- and late-spawning adults in Pamunkey River spawning aggregations in either year. The donor and recipient populations exhibited significant genetic differentiation (χ 2 = 27.4, p = 0.003), however, indicating that the stocking program carries a risk of outbreeding depression. Because the two river populations are genetically divergent, replenishment of the James population with Pamunkey fry may be detectable in the future as heterozygote deficits and linkage disequilibria in the James River population. In an analysis of broodstock and their hatchery-reared progeny, microsatellites proved efficient for family analysis, unambiguously determining the parentage of 100% of the hatchery-reared fry studied. Genetic analysis indicated that breeding procedures may result in high levels of reproductive variance. 相似文献
709.
Ronald P. Young James L. DuBard Leslie E. Sparks 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1412-1418
The onset of electrical breakdown in dust layers has been studied for hand-deposited dust layers in a parallel plate geometry. It was found that the breakdown was an ordinary electron avalanche process originating in voids within the dust layer and obeying Paschen’s Law. The size of voids where breakdown occurs was in the range of 10 to 20 μm for the layers used. The distribution of particle sizes in a sample Influences its breakdown through changes in the average void dimension where breakdown takes place. Water vapor in the test environment, which affects the electrical conduction mechanism prior to breakdown, lowered the average electric field required to initiate breakdown. Moderate compaction of the sample had little or no effect on its breakdown behavior. 相似文献
710.
Thomas J. Overcamp Hsien-cheng Chang C. P. Leslie Grady Jr. 《Journal of the Air & Waste Management Association (1995)》2013,63(5):753-759
An integrated theory is developed to describe the steadystate operation of a suspended-growth bioscrubber for the control of biodegradable, volatile organic gases. The bioscrubber consists of an N-stage absorber and an oxidation reactor. A biomass slurry is circulated between the absorber and the oxidation reactor, t he pollutant is absorbed and partially oxidized in the absorber. Oxidation is completed in the oxidation reactor. Predictions of the theory show that the removal efficiency is a function of Henry's Law constant for the pollutant, the ratio of the liquid flow rate to the gas flow rate, and the number of stages. Since high efficiencies can be achieved for soluble, biodegradable, volatile organic compounds, such systems have the potential to be a low-cost control method. 相似文献