全文获取类型
收费全文 | 1989篇 |
免费 | 250篇 |
国内免费 | 1017篇 |
专业分类
安全科学 | 34篇 |
废物处理 | 41篇 |
环保管理 | 351篇 |
综合类 | 1841篇 |
基础理论 | 494篇 |
污染及防治 | 191篇 |
评价与监测 | 186篇 |
社会与环境 | 94篇 |
灾害及防治 | 24篇 |
出版年
2024年 | 9篇 |
2023年 | 34篇 |
2022年 | 73篇 |
2021年 | 76篇 |
2020年 | 91篇 |
2019年 | 101篇 |
2018年 | 71篇 |
2017年 | 97篇 |
2016年 | 130篇 |
2015年 | 161篇 |
2014年 | 142篇 |
2013年 | 268篇 |
2012年 | 204篇 |
2011年 | 223篇 |
2010年 | 156篇 |
2009年 | 173篇 |
2008年 | 129篇 |
2007年 | 148篇 |
2006年 | 168篇 |
2005年 | 113篇 |
2004年 | 105篇 |
2003年 | 77篇 |
2002年 | 71篇 |
2001年 | 59篇 |
2000年 | 53篇 |
1999年 | 41篇 |
1998年 | 44篇 |
1997年 | 44篇 |
1996年 | 30篇 |
1995年 | 16篇 |
1994年 | 20篇 |
1993年 | 11篇 |
1992年 | 10篇 |
1991年 | 10篇 |
1990年 | 13篇 |
1989年 | 8篇 |
1988年 | 7篇 |
1987年 | 8篇 |
1986年 | 3篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1981年 | 6篇 |
1980年 | 15篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1972年 | 2篇 |
排序方式: 共有3256条查询结果,搜索用时 15 毫秒
841.
Rasmus B. Lauridsen Brian Kronvang Nikolai Friberg 《Water, Air, & Soil Pollution: Focus》2006,6(5-6):423-432
In a total of 189 water samples collected from Danish streams no traces of the pyrethroid esfenvalerate were detected. However,
pyrethroids have previously been found in sediments in 9 out of 30 streams investigated. We found that the shredding activity
of the Trichopteran Sericostoma personatum and the amphipod Gammarus pulex was significantly reduced with increased concentration of the pyrethroid lambda-cyhalohtrin adsorbed to the leaves on which
they fed. Predation rate on the Plecopteran Leuctra nigra by the leech Erpobdella octoculata increased significantly with increasing concentration of lambda-cyhalothrin on the leaves on which L. nigra was fed. Our results clearly indicate that the ongoing monitoring of pesticides is likely to underestimate pyrethroid occurrence
and that sediment-bound pyrethroids have a potential negative impact on ecosystem function and biotic interactions in streams. 相似文献
842.
ESTIMATING TMDL BACKGROUND SUSPENDED SEDIMENT LOADING TO GREAT LAKES TRIBUTARIES FROM EXISTING DATA1
Peter J. Whiting 《Journal of the American Water Resources Association》2006,42(3):769-776
ABSTRACT: The total maximum daily load (TMDL) for suspended sediment is the maximum quantity of suspended sediment that can enter a waterway without affecting the beneficial uses of the waterway. It is calculated as the sum of permissible allotments of point sources of suspended sediment, permissible allotments of nonpoint sources of suspended sediment, background (natural) loading of suspended sediment, and a margin of safety. The goal of this project was to develop methods for estimating background levels of sediment loads in tributaries of the Great Lakes. Such quantification is key to determining permissible TMDL in waters that do not meet water quality standards under the Clean Water Act of 1972. Suspended sediment loading for 46 rivers was estimated from data collected at U.S. Geological Survey (USGS) gages. Land use and physiographic attributes were estimated for these gaged basins with a geographic information system (GIS). Basin attributes and sediment yield data are the basis for examining two approaches to estimating background suspended sediment loads. One method, based upon envelope curves of sediment yield and drainage area, will be shown to have considerable merit. A second method, based upon correlation of sediment yield to various basin attributes such as drainage area and land use, will be shown to be fraught with difficulties. 相似文献
843.
Steven W. Effler David A. Matthews Josef W. Kaser Anthony R. Prestigiacomo David G. Smith 《Journal of the American Water Resources Association》2006,42(6):1697-1710
Abstract: The impacts of runoff events on external suspended solids loading to Schoharie Reservoir, New York, and patterns of light scattering and sediment deposition in this reservoir are assessed. The assessment is based on monitoring of suspended solids concentrations in the reservoir's primary tributary, detailed vertical profiles of optical backscattering (a surrogate measure of light scattering) in the reservoir water column, and analysis of sediment trap collections, over a seven-month interval of high runoff. These impacts are reported to be tightly temporally coupled and strongly positively related to the magnitude of runoff events. The primary tributary entered the reservoir as a plunging inflow during runoff events, causing conspicuous subsurface peaks in light scattering, with vertical patterns that varied strongly for different events. Deposition quantified by near-bottom trap deployments is reported to be more representative than results from metalimnetic deployments that were generally within, rather than below, the turbid layers. Direct inputs of sediment, transported by density currents, are found to drive deposition, rather than resuspension/redeposition. More than 50 percent of the reported deposition occurred in less than 15 percent of the study period, associated with the four largest runoff events. 相似文献
844.
A. N. Macgregor D. R. Keeney 《Journal of the American Water Resources Association》1973,9(6):1153-1158
ABSTRACT: Renewed (de novo) synthesis of methane gas was shown to occur when samples of lake sediment were dispersed on glass beads and incubated in a helium atmosphere at 23°C. Under the above conditions, sediment samples from hardwater and softwater lakes generated up to 440 nanomoles and 80 nanomoles per ml of sediment per two days, respectively. At the time of collection, sediment samples possessed approximately similar amounts of “native” methane. Nitrate, sulfate, and acetylene were shown to suppress methane synthesis by sediment incubated as described. 相似文献
845.
Fernández Pilar Rose Neil L. Vilanova Rosa M. Grimalt Joan O. 《Water, Air, & Soil Pollution: Focus》2002,2(2):261-274
Spheroidal carbonaceous particles (SCP) and polycyclicaromatic hydrocarbons (PAH) have been measured in the dated sediment cores of 10 remote lakes distributed across Europe. The geographic trends were evaluated by examination of the superficial sediment fluxes and total sediment inventories. The highest levels of both markers were observed in the Eastern European lakes whereas the minimal values corresponded to the lake located in the Arctic. However, this SCP-PAH correlation was not observed after exclusion of the end member lakes from the series. The temporal trends of both pollutant markers are consistent with the history of pyrolytic emissions over Europe. However, the downcore SCP distributions are shorter than the PAH profiles in nearly all lakes. The differences are probably related to the different size particle fractions involved in the measurement of each marker, >5 and >1 m for SCP and PAH, respectively. Thus, the two proxies probably reflect pollution inputs from closer (SCP) and more distant sites (PAH). 相似文献
846.
A case study of microwave processing of metal hydroxide sediment sludge from printed circuit board manufacturing wash water 总被引:2,自引:0,他引:2
The large quantity of wash water used in the electroplating and etching process in the manufacturing of printed circuit boards (PCBs) contains a high level of heavy metal ions (Cu++, Zn++, Ni++, Cr+++, Pb++). These potentially toxic ions are removed from the wash water effluent through a polyelectrolyte flocculation and hydroxide precipitation process during which a hydroxide sediment sludge rich in metal ions and polymers is generated. This sediment sludge possesses some unique characteristics and properties in terms of composition, fine particle size distribution, high specific surface area, and a tendency to agglomerate after drying. Direct disposal of this classified “special waste” (Department of Environment of Northern Ireland, The Special Waste Regulations, Northern Ireland, 1998) at landfill sites may cause serious soil and underground water pollution through a gradual ionic leaching process. This paper describes an experimental investigation, exploratory in nature, which employs microwave radiation for detoxification of the sediment sludge through microwave heating, drying and metal ion immobilization within the sediment solids. The effectiveness of microwave assisted binding and immobilization of the metal ions within the sediment solids was studied in conjunction with an evaluation of microwave energy efficiency in comparison to the more conventional convective heating and drying processes. Given a sufficient amount of microwave radiation, leaching of Cu2+ and Pb2+ was reduced by 2700% and 1080%, respectively, over a period of 12 weeks, and further leaching was not detectable within six months at simulated local landfill aqueous conditions. This paper also attempts, through experimental observation, to add to the very limited understanding of the complex interactions and binding of free metal ions with the polymeric materials and metal hydroxides under the influence of an electromagnetic field. The high specific surface of the sediment solids and their adsorption properties were further explored and characterized in a study of adsorption of reactive dyes by the microwave processed solids. 相似文献
847.
采用淡水沉积物质量基准和微生物毒性试验方法,对疏浚前后五里湖沉积物提取液和全底泥沉积物的生态毒性进行了研究与分析.结果表明,疏浚后,沉积物中各重金属污染物的总体含量均显著降低,但是铬、铅和镍的含量仍然分布在阈值效应低值(TEL)和可能效应水平值(PEL)之间的灰色区域,仍可能对水体生态系统产生不良影响;疏浚后1个月,沉积物提取液中发光菌发光试验的EC50值降低约50%,毒性增加近1倍;与疏浚前相比,全底泥沉积物的细菌毒性试验的EC50值降低11%~30%;全底泥月芽藻毒性试验的EC50值也有显著降低. 相似文献
848.
通过快速释放实验,研究了太湖东北部营养水平不同的梅梁湾、贡湖湾和胥口湾3个湖区表层沉积物中可溶性氮、磷的季节性变化.结果表明,沉积物总磷(TP)与其释放的可溶性总磷(DTP)在春、夏两季显著相关并且以可溶性有机磷(DOP)为主;春、夏两季DOP与可溶性无机磷(DIP)的形态间转化较秋、冬两季更为活跃.藻型湖区沉积物的总氮(TN)多为夏季减少,而清洁型湖区则为夏季大幅增加;沉积物释放的NH4+-N以夏、冬两季居多,夏季达到最大值;沉积物释放的NO3--N夏季大幅度增加,冬季较少.清洁型湖区夏季沉积物的TN及其释放的NH4+-N、NO3--N显著高于藻型湖区. 相似文献
849.
850.