全文获取类型
收费全文 | 1808篇 |
免费 | 28篇 |
国内免费 | 15篇 |
专业分类
安全科学 | 53篇 |
废物处理 | 68篇 |
环保管理 | 301篇 |
综合类 | 303篇 |
基础理论 | 431篇 |
环境理论 | 4篇 |
污染及防治 | 469篇 |
评价与监测 | 134篇 |
社会与环境 | 83篇 |
灾害及防治 | 5篇 |
出版年
2023年 | 19篇 |
2022年 | 20篇 |
2021年 | 25篇 |
2020年 | 24篇 |
2019年 | 23篇 |
2018年 | 39篇 |
2017年 | 47篇 |
2016年 | 43篇 |
2015年 | 46篇 |
2014年 | 50篇 |
2013年 | 127篇 |
2012年 | 73篇 |
2011年 | 108篇 |
2010年 | 77篇 |
2009年 | 92篇 |
2008年 | 95篇 |
2007年 | 115篇 |
2006年 | 84篇 |
2005年 | 74篇 |
2004年 | 72篇 |
2003年 | 67篇 |
2002年 | 78篇 |
2001年 | 33篇 |
2000年 | 26篇 |
1999年 | 18篇 |
1998年 | 19篇 |
1997年 | 24篇 |
1996年 | 20篇 |
1995年 | 23篇 |
1994年 | 25篇 |
1993年 | 13篇 |
1992年 | 16篇 |
1991年 | 15篇 |
1990年 | 12篇 |
1989年 | 12篇 |
1988年 | 17篇 |
1987年 | 12篇 |
1986年 | 15篇 |
1984年 | 8篇 |
1983年 | 10篇 |
1982年 | 11篇 |
1981年 | 9篇 |
1980年 | 7篇 |
1979年 | 10篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 6篇 |
1974年 | 6篇 |
1955年 | 5篇 |
1954年 | 8篇 |
排序方式: 共有1851条查询结果,搜索用时 593 毫秒
561.
Verta M Salo S Korhonen M Assmuth T Kiviranta H Koistinen J Ruokojärvi P Isosaari P Bergqvist PA Tysklind M Cato I Vikelsøe J Larsen MM 《Chemosphere》2007,67(9):1762-1775
Recent survey results for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs, dioxins) in Baltic Sea sediments from Finland, Sweden and Denmark were merged with previously published Baltic Sea data. Regional distribution of concentration levels, differences in congener patterns, and temporal changes in sediment profiles were examined. One of the main objectives was to study if any major point sources for different PCDD/F congeners could be identified on a regional scale, based on sediment records. The survey confirmed the impact of chlorophenol production derived highly chlorinated PCDF-congeners on the total toxicity in sediments in the Gulf of Finland near the Kymijoki river estuary. Signatures of other point sources or combined point sources pertinent to specific industry branches or particular production processes (such as pulp bleaching, vinyl chloride production, thermal processes) may be discerned. However, the findings did not support any of the known point sources significantly influencing those congeners that are most abundant in Baltic herring and salmon. Instead, regional distributions in the Baltic Sea indicate that atmospheric deposition may act as a major source for those congeners and especially for 2,3,4,7,8-PeCDF. There were clear indications of declines in levels in sediment in some areas, but generally the levels of highly chlorinated PCDD/Fs on the northern coast of the Gulf of Finland were still high when compared with other areas of the Baltic Sea. Major areas with data gaps cover the south-eastern and eastern coastal regions of the Baltic Proper and the southern Gulf of Finland. 相似文献
562.
We explored temporal trends of young-of-year (YOY) fishes caught in bottom trawl hauls at an established offshore monitoring
site in Lake Erie in fall during 1961–2001. Sampling was conducted during morning, afternoon, and night in each year. Catches
per hour (CPH) of alewife (Alosa pseudoharengus) YOY were relatively low and exhibited no temporal trend. This result was consistent with the species’ intolerance to Lake
Erie’s adverse winter water temperatures. Gizzard shad (Dorosoma cepedianum) YOY decreased sharply after 1991, which was consistent with recent oligotrophication of the lake. Following the establishment
in 1979 and rapid increase of white perch (Morone americana) YOY, white bass (Morone chrysops) and freshwater drum (Aplodinotus grunniens) YOY decreased. Trout-perch (Percopsis omiscomaycus) YOY decreased during 1986–1991, but recovered to previous levels during 1991–2001. The recovery coincided with the resurgence
of mayflies (Ephemoptera) in the lake. CPH of spottail shiner (Notropis hudsonius) and emerald shiner (N. atherinoides) YOY exhibited no temporal trend between 1961 and the late 1970s to early 1980s. CPH of yellow perch (Perca flavescens) YOY decreased during 1961–1988, and walleye (Sander vitreum) YOY increased overall during the time series. These observations were consistent with published studies of adults in the
region. CPH of 4 of the 10 species of YOY considered were greatest during night. CPH for walleye YOY was higher in the morning
than in the afternoon, but there was no significant difference between night and morning abundances. The results suggest that
(1) CPH of YOY fishes may be a useful monitoring tool for Lake Erie, and (2) offshore monitoring programs that do not include
night sampling periods may underestimate recruitment for several common species. 相似文献
563.
Light nonaqueous-phase liquids (LNAPLs) such as gasoline and diesel fuel are among the most common causes of soil and groundwater contamination. Dissolution and subsequent advective transport of LNAPL components can negatively impact water supplies, while biodegradation is thought to be an important sink for this class of contaminants. We present a laboratory investigation of the effect of a water-table fluctuation on dissolution and biodegradation of a multi-component LNAPL (85% hexadecane, 5% toluene, 5% ethylbenzene, and 5% 2-methylnapthalene on a molar basis) in a pair of similar model aquifers (80 cm x 50 cm x 3 cm), one of which was subjected to a water-table fluctuation. Water-table fluctuation resulted in LNAPL and air entrapment below the water table, an increase in the vertical extent of the LNAPL source zone (by factor 6.7), and an increase in the volume of water passing through the source zone (by factor ~18). Effluent concentrations of dissolved LNAPL components were substantially higher and those of dissolved nitrate lower in the model aquifer where a fluctuation had been induced. Thus, water-table fluctuation led to enhanced biodegradation activity (28.3 mmol of nitrate consumed compared to 16.3 mmol in the model without fluctuation) as well as enhanced dissolution of LNAPL components. Despite the increased biodegradation, fluctuation led to increased elution of dissolved LNAPL components from the system (by factors 10-20). Hence, water-table fluctuations in LNAPL-contaminated aquifers might be expected to result in increased exposure of downgradient receptors to LNAPL components. Accordingly, water-table fluctuations in contaminated aquifers are probably undesirable unless the LNAPL is of minimal solubility or the dissolved-phase plume is not expected to reach a receptor due to distance or the presence of some form of containment. 相似文献
564.
Hilber T Maier J Scheffknecht G Agraniotis M Grammelis P Kakaras E Glorius T Becker U Derichs W Schiffer HP De Jong M Torri L 《Journal of the Air & Waste Management Association (1995)》2007,57(10):1178-1189
The 1999/31 Elemental Carbon Directive sets strict rules on the disposal of untreated municipal solid waste in the European Union countries and forces a reduction of the biodegradable quantities disposed off to landfills up to 35% of the amount produced in 1995 in the coming decade. More environmentally friendly waste management options shall be promoted under the framework of the Community Waste Strategy ([96] 399 Final). In this context, the production and thermal use of solid recovered fuels (SRFs), derived from nonhazardous bioresidues and mixed- and mono-waste streams, could be a key element in a future waste management system. Within the scope of the European Demonstration Project, RECOFUEL, SRF cocombustion was demonstrated in two large-scale lignite-fired coal boilers at RWE power station in Weisweiler, Germany. As a consequence of the high biogenic share of the cocombusted material, this approach can be considered beneficial following European Directive 2001/77/EC on electricity from renewable energy sources (directive). During the experimental campaign, the share of SRF in the overall thermal input was adjusted to approximately 2%, resulting into a feeding rate of approximately 25 t/hr. The measurement campaign included boiler measurements in different locations, fuel and ash sampling, and its characterization. The corrosion rates were monitored by dedicated corrosion probes. The overall results showed no significant influence of SRF cocombustion on boiler operation, emissions behavior, and residues quality for the thermal shares applied. Also, no effect of the increased chlorine concentration of the recovered fuel was observed in the flue gas path after the desulfurization unit. 相似文献
565.
Contaminant transport is generally considered to be a key factor when assessing and classifying the environmental risk of polluted areas. In the study presented here, a steady-state approach was applied to obtain estimates of the transit time and concentration of the pesticide metabolite BAM (2,6-dichlorobenzoamide) at a site where it is contaminating a municipal drinking water supply. A Monte Carlo simulation technique was used to quantify the uncertainty of the results and to evaluate the sensitivity of the used parameters. The adopted approach yielded an estimated median transit time of 10 y for the BAM transport from the polluted site to the water supply. Soil organic carbon content in the unsaturated zone and the hydraulic conductivity in the saturated zone explained 44% and 23% of the uncertainty in the transit time estimate, respectively. The sensitivity analysis showed that the dilution factor due to regional groundwater flow and the soil organic carbon content at the polluted site explained 53% and 31% of the uncertainty of concentration estimates, respectively. In conclusion, the adopted steady-state approach can be used to obtain reliable first estimates of transit time and concentration, but to improve concentration predictions of degrading contaminants, a dynamic model is probably required. 相似文献
566.
Ruth Offermann Thilo Seidenberger Daniela Thrän Martin Kaltschmitt Sergey Zinoviev Stanislav Miertus 《Mitigation and Adaptation Strategies for Global Change》2011,16(1):103-115
So far, various studies assessed global biomass potentials and came up with widely varying results. Existing potential estimates
range from 0 EJ/a up to more than 1,550 EJ/a which corresponds to about three times the current global primary energy consumption.
This paper provides an overview of the available research on bioenergy potentials and reviews the different assessments qualitative
way with the objective to interpret previous research in an integrated way. In the context of this paper we understand bioenergy
as energy from biomass sources including energy crops, residues, byproducts and wastes from agriculture, forestry, food production
and waste management. In this review special attention was paid to the difference between residue and energy potentials, land
availability estimates, and the geographical resolution of existing potential estimates. The majority of studies concentrate
on energy crop potentials retrieved from surplus agricultural land and only few publications assess global potentials separated
by different world regions. It results that land allocated to the exclusive production of energy crops varies from 0 to 7,000 ha,
depending on land category and scenario assumptions. Only a small number of available potential assessments consider residue
potentials as well as energy crop potentials from degraded land. Future energy crop potentials are assumed to vary in the
mean from 200 to 600 EJ/yr. In contrast residue potentials are expected to contribute between 62 and 325 EJ/yr. The highest
potentials are assigned to Asia, Africa and South America while Europe, North America and the Pacific region contribute minor
parts to the global potential. 相似文献
567.
568.
569.
Brigitte Simon-Bouy Agnès Taillandier Delphine Fauvert Isabelle Brun-Heath Jean-Louis Serre Carmen G. Armengod Martin G. Bialer Michèle Mathieu Jacques Cousin David Chitayat Jan Liebelt Barbara Feldman Marion Gérard-Blanluet Stefani Körtge-Jung Cath King Hannele Laivuori Martine Le Merrer Sarju Mehta Christina Jern Saba Sharif Fabienne Prieur Gabriele Gillessen-Kaesbach Andreas Zankl Etienne Mornet 《黑龙江环境通报》2008,28(11):993-998
570.
Kaufman MM 《Environmental management》2000,26(1):89-97
/ To test the effectiveness of Michigan's soil erosion control law, 30 construction sites were evaluated in the east-central part of the state. The analytical framework lumped nine best management practices (BMPs) most closely related to the law into three categories: slope stabilization, soil stabilization, and water management. All sites were in the land clearing or foundation/framing stage of construction and were evaluated within 2 days after a rainfall event. Only four of the sites performed above the mean of the scoring scale, with the categorical scoring of BMPs indicating the worst performance for slope stabilization measures. The poor results suggest a failure to integrate scientific knowledge of erosion control with policy. A fundamental problem is the lack of basic site data on soil, topography, and hydrology, resulting in the incorrect application of BMPs, such as staging, filter fences, and berms. The current institutional framework for soil erosion control also provides disincentives to mitigate local erosion problems. 相似文献