首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   96篇
  免费   1篇
安全科学   7篇
废物处理   4篇
环保管理   23篇
综合类   27篇
基础理论   17篇
污染及防治   16篇
评价与监测   1篇
社会与环境   1篇
灾害及防治   1篇
  2023年   1篇
  2020年   2篇
  2019年   2篇
  2018年   1篇
  2017年   1篇
  2016年   2篇
  2015年   2篇
  2014年   1篇
  2013年   7篇
  2012年   4篇
  2011年   1篇
  2010年   3篇
  2009年   1篇
  2008年   5篇
  2007年   3篇
  2006年   3篇
  2005年   4篇
  2004年   1篇
  2003年   1篇
  2002年   9篇
  2001年   1篇
  2000年   6篇
  1999年   2篇
  1998年   1篇
  1995年   3篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1989年   1篇
  1988年   1篇
  1987年   2篇
  1985年   1篇
  1982年   1篇
  1981年   1篇
  1979年   1篇
  1977年   1篇
  1975年   1篇
  1973年   1篇
  1969年   2篇
  1960年   2篇
  1959年   4篇
  1958年   2篇
  1957年   1篇
  1955年   1篇
  1954年   3篇
  1952年   1篇
排序方式: 共有97条查询结果,搜索用时 46 毫秒
41.
In the past few decades huge amounts of solid and paste-like wastes of domestic and industrial origin have been deposited on sanitary landfills worldwide. Only a small proportion was incinerated, where incineration plants were available. Since primary resources, such as ores for metal production or crude oil for the production of gasoline, diesel, solvents and plastics, or coal and natural gas as sources for energy or chemicals are not available in unlimited quantities, and because the deposition of residues, wastes and worn-out commodities on sanitary landfills causes pollution of the atmosphere, the soil and the groundwater due to hazardous gaseous emissions and toxic leachates, wastes from households and from industry must be avoided or minimized at an early stage. Whenever waste material can be recycled it must be re-introduced into production processes and the non-recyclable fractions should be used as a fuel for energy recovery. After incineration, the highly toxic dust fractions of ashes and slags resulting from burning the wastes should be deposited on sanitary landfills, while the granulated mineral slag fractions could be used as a substitute for the sand in cement as a construction material. Here we review various processes for the treatment of organic fractions of differently composed wastes to upgrade them to more valuable, re-usable products or at least to recover their energy content. Upgrading processes of organic wastes include composting, biogas fermentation, production of organic acids and solvents, and biopolymer or biosurfactants production. We also include biological purification procedures for the most important components of wastes, such as chitin from the shells of Crustaceae. Typical examples from pilot-scale or full-scale studies are discussed for each process.  相似文献   
42.
To investigate the effects of golf course construction and operation on the water chemistry of Shield streams, we compared the water chemistry in streams draining golf courses under construction (2) and in operation (5) to streams in forested reference locations and to upstream sites where available. Streams were more alkaline and higher in base cation and nitrate concentrations downstream of operational golf courses. Levels of these parameters and total phosphorus increased over time in several streams during golf course construction through to operation. There was evidence of inputs of mercury to streams on two of the operational courses. Nutrient (phosphorus and nitrogen) concentrations were significantly related to the area of unmanaged vegetation in a 30 x 30 m area on either side of the sampling sites, and to River Bank Quality Index scores, suggesting that maintaining vegetated buffers along the stream on golf courses will reduce in-stream nutrient concentrations.  相似文献   
43.
44.
Organochlorine compounds in a three-step terrestrial food chain   总被引:1,自引:0,他引:1  
The concentrations of 15 organochlorine chemicals (PCBs and pesticides) were studied in a Central European oak wood food chain system: Great tit (Parus major), caterpillars (Tortrix viridana, Operophtera brumata, Erannis defoliaria), and oak-leaves (Quercus robur). Juvenile tits receive organochlorines from the mother via egg transfer and, eventually to a greater extent, from the caterpillar food source during nestling period. The concentrations of PCB 153 (2,2′,4,4′,5,5′-hexachlorobiphenyl, the most abundant in this study) was found in leaf material at ca. 1 ng/g, in caterpillars 10 ng/g, and in bird eggs 170 ng/g on an average and on a dry mass basis.  相似文献   
45.
ABSTRACT: Hydrologic landscapes are multiples or variations of fundamental hydrologic landscape units. A fundamental hydrologic landscape unit is defined on the basis of land‐surface form, geology, and climate. The basic land‐surface form of a fundamental hydrologic landscape unit is an upland separated from a lowland by an intervening steeper slope. Fundamental hydrologic landscape units have a complete hydrologic system consisting of surface runoff, ground‐water flow, and interaction with atmospheric water. By describing actual landscapes in terms of land‐surface slope, hydraulic properties of soils and geologic framework, and the difference between precipitation and evapotranspiration, the hydrologic system of actual landscapes can be conceptualized in a uniform way. This conceptual framework can then be the foundation for design of studies and data networks, syntheses of information on local to national scales, and comparison of process research across small study units in a variety of settings. The Crow Wing River watershed in central Minnesota is used as an example of evaluating stream discharge in the context of hydrologic landscapes. Lake‐research watersheds in Wisconsin, Minnesota, North Dakota, and Nebraska are used as an example of using the hydrologic‐land‐scapes concept to evaluate the effect of ground water on the degree of mineralization and major‐ion chemistry of lakes that lie within ground‐water flow systems.  相似文献   
46.
Agriculture is a key land user implicated in the causes of, and solutions to, the problem of biodiversity decline. The development, in the late 1990s, of farm biodiversity action plans (farm BAPs) represents an important step towards achieving greater farmer involvement in biodiversity and is the first specific attempt to devise a practical mechanism for meeting biodiversity targets at the farm level. In this paper the processes surrounding the design and implementation of farm BAPs are used to explore how farmers are responding to the biodiversity issue and to highlight challenges and opportunities being faced by the organizations delivering biodiversity to the farming community. It describes the formulation and operation of farm BAPs, and then moves on to present two conceptual domains, governance and ecological modernization, which provide a framework for interpreting the emergence of farm BAPs. Following a brief elaboration of methodology, the paper presents and discusses selected findings from empirical research into farm BAPs across the UK.  相似文献   
47.
48.
The Summitville Mine was a high-elevation (3500 m) gold mine in southwestern Colorado. The mine was abandoned in 1992, leaving approximately 200 ha of disturbance comprised partially of an open pit, a cyanide heap leach pad, and two large waste rock piles. Reclamation of these mine facilities is challenging due to extreme climatic conditions in conjunction with high acid-production potential and low organic matter content of waste materials on site. In addition, stockpiled topsoil at the site is acidic and biologically inactive due to long-term storage, and may not be suitable for plant growth. The purpose of this study was to evaluate the effects of organic amendments (mushroom compost vs. biosolids) and topsoil (stockpiled vs. nonstockpiled) on aboveground biomass and plant trace element uptake. An on-site field study was established in 1995 to identify the most effective combination of treatments for successful reclamation of on-site waste rock materials. Incorporation of organic matter significantly increased aboveground biomass, with mushroom compost being more effective than biosolids, but did not significantly influence trace element uptake. Conversely, the use of topsoil did not affect aboveground biomass, but did influence trace element uptake. Treatments that received topsoil supported plant growth with significantly higher trace element tissue concentrations than treatments that did not receive topsoil. In general, it was found that waste rock could be directly revegetated when properly neutralized, fertilized, and amended with organic matter. Additionally, stockpiled topsoil, when neutralized with lime, supported plant growth equivalent to that on nonstockpiled topsoil.  相似文献   
49.
Meiofauna was sampled using SCUBA along 4 transects from 5 to 30 m depth in Algoa Bay, South Africa. Substrates were well-sorted medium to fine sands with traces of sewage pollution in some areas. Meiofauna numbers recorded in the upper 10 cm of sediment were 55 to 584 10 cm-2, but total numbers, including deeper-living animals, were 680 to 2090 10 cm-2 at 6 stations. Longer cores showed meiofauna to be abundant down to at least 35 cm, and samples of interstitial water taken from this depth in the sediment were 7% saturated with oxygen. This is the first detailed record of meiofauna penetration into sub-littoral sand and stresses the need for long cores for quantitative work. Nematode numbers were found to be significantly related to nitrogen in the sand while interstitial harpacticoid numbers were related to median particle diameters, which determine pore space. Effects of sewage were slight and only one station showed notable enrichment, increased meiofaunal numbers and extreme dominance by nematodes.  相似文献   
50.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号