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   246篇
  免费   2篇
  国内免费   6篇
安全科学   5篇
废物处理   9篇
环保管理   33篇
综合类   26篇
基础理论   46篇
污染及防治   84篇
评价与监测   41篇
社会与环境   10篇
  2023年   13篇
  2022年   18篇
  2021年   23篇
  2020年   3篇
  2019年   6篇
  2018年   7篇
  2017年   11篇
  2016年   9篇
  2015年   2篇
  2014年   8篇
  2013年   30篇
  2012年   12篇
  2011年   13篇
  2010年   6篇
  2009年   10篇
  2008年   9篇
  2007年   13篇
  2006年   7篇
  2005年   7篇
  2004年   4篇
  2003年   4篇
  2002年   4篇
  2001年   1篇
  2000年   1篇
  1999年   1篇
  1998年   4篇
  1997年   2篇
  1996年   2篇
  1994年   1篇
  1993年   2篇
  1992年   1篇
  1991年   2篇
  1990年   5篇
  1989年   1篇
  1982年   1篇
  1971年   2篇
  1966年   2篇
  1964年   1篇
  1963年   2篇
  1961年   1篇
  1958年   1篇
  1957年   2篇
排序方式: 共有254条查询结果,搜索用时 15 毫秒
1.
Prices for ferro-alloys have hardened due to the closure of plants in developed countries on account of increasingly stringent pollution control legislation, resulting in a higher cost of production. A ferro-alloy industry with a capacity of 80000 MT per annum was selected to study the nature of pollution. Because of the objectionable nature of polluting air in and around the plant it was located in a rural area where there was no other industry. The area was agriculturally active and there was no effective control system for this plant.The quality of ambient air around the plant site is discussed in this paper along with the meteorological conditions. The maximum concentration of suspended particulate matter (SPM) was 768 µg/NM3 downwind of the plant, minimum 184 µg/NM3, and the average was more than 446 µg/NM3. The presence of heavy metals, viz. Fe, Mn, Cr and Pb, was also assessed. The concentration of Fe was 50 µg/NM3 downwind and 10 µg/NM3 upwind. The concentration of other metals followed a similar trend.  相似文献   
2.
Most writers on resource management presume that local populations, if they act in their self-interest, seldom conserve or protect natural resources without external intervention or privatization. Using the example of forest management by villagers in the Indian Himalayas, this paper argues that rural populations can often use resources sustainably and successfully, even under assumptions of self-interested rationality. Under a set of specified social and environmental conditions, conditions that prevail in large areas of the Himalayas and may also exist in other mountain regions, community institutions are more efficient in managing resources than either private individuals or the central government. In advancing this argument, the paper undermines the often dogmatic belief in the universal superiority of private forms of ownership and management.  相似文献   
3.
Activated carbon, developed from fertilizer waste, has been used for the removal of Hg2+, Cr6+, Pb2+, and Cu2+. Mass transfer kinetic approach has been successfully applied for the determination of various parameters necessary for designing a fixed-bed absorber. Parameters selected are the length of the (PAZ) primary adsorption zone (δ), total time involved for the establishment of primary adsorption zone (tx), mass rate of flow to the absorber (Fm), time for primary adsorption zone to move down its length (tδ), amount of adsorbate adsorbed in PAZ from breakpoint to exhaustion (Ms), fractional capacity (f), time of initial formation of PAZ (tf) and per cent saturation of column at break point. Chemical regeneration has been achieved with 1 M HNO3.  相似文献   
4.
Environmental Science and Pollution Research - Erosion of soil by water coupled with human activities is considered as one of the...  相似文献   
5.
Conservation and development practitioners increasingly promote community forestry as a way to conserve ecosystem services, consolidate resource rights, and reduce poverty. However, outcomes of community forestry have been mixed; many initiatives failed to achieve intended objectives. There is a rich literature on institutional arrangements of community forestry, but there has been little effort to examine the role of socioeconomic, market, and biophysical factors in shaping both land‐cover change dynamics and individual and collective livelihood outcomes. We systematically reviewed the peer‐reviewed literature on community forestry to examine and quantify existing knowledge gaps in the community‐forestry literature relative to these factors. In examining 697 cases of community forest management (CFM), extracted from 267 peer‐reviewed publications, we found 3 key trends that limit understanding of community forestry. First, we found substantial data gaps linking population dynamics, market forces, and biophysical characteristics to both environmental and livelihood outcomes. Second, most studies focused on environmental outcomes, and the majority of studies that assessed socioeconomic outcomes relied on qualitative data, making comparisons across cases difficult. Finally, there was a heavy bias toward studies on South Asian forests, indicating that the literature on community forestry may not be representative of decentralization policies and CFM globally.  相似文献   
6.
Many argue that monitoring conducted exclusively by scientists is insufficient to address ongoing environmental challenges. One solution entails the use of mobile digital devices in participatory monitoring (PM) programs. But how digital data entry affects programs with varying levels of stakeholder participation, from nonscientists collecting field data to nonscientists administering every step of a monitoring program, remains unclear. We reviewed the successes, in terms of management interventions and sustainability, of 107 monitoring programs described in the literature (hereafter programs) and compared these with case studies from our PM experiences in Australia, Canada, Ethiopia, Ghana, Greenland, and Vietnam (hereafter cases). Our literature review showed that participatory programs were less likely to use digital devices, and 2 of our 3 more participatory cases were also slow to adopt digital data entry. Programs that were participatory and used digital devices were more likely to report management actions, which was consistent with cases in Ethiopia, Greenland, and Australia. Programs engaging volunteers were more frequently reported as ongoing, but those involving digital data entry were less often sustained when data collectors were volunteers. For the Vietnamese and Canadian cases, sustainability was undermined by a mismatch in stakeholder objectives. In the Ghanaian case, complex field protocols diminished monitoring sustainability. Innovative technologies attract interest, but the foundation of effective participatory adaptive monitoring depends more on collaboratively defined questions, objectives, conceptual models, and monitoring approaches. When this foundation is built through effective partnerships, digital data entry can enable the collection of more data of higher quality. Without this foundation, or when implemented ineffectively or unnecessarily, digital data entry can be an additional expense that distracts from core monitoring objectives and undermines project sustainability. The appropriate role of digital data entry in PM likely depends more on the context in which it is used and less on the technology itself.  相似文献   
7.
Environmental Science and Pollution Research - In this paper, the combustion characteristics of biogas in a Porous Radiant Burner (PRBBG) designed for domestic cooking appliances are presented....  相似文献   
8.
This investigation was undertaken to determine the effect of culture filtrates of different isolates of Fusarium oxysporum f. sp. lycopersici on mortality of Meloidogyne incognita juveniles and egg hatching. It was observed that different concentrations including standard extract (S.E), 1:10 and 1:100 dilutions of all fungal filtrates inhibited egg hatch when compared with control. Minimum mortality and maximum hatching was observed in BRT (showing least mortality) isolate of F. oxysporum, while maximum mortality and minimum egg hatching was recorded in BGT (showing maximum mortality) isolate. Larval mortality was decreased with a decrease in concentration and the least mortality was observed in 1:100 when compared with SE and 1:10. The potentiality of both the isolates (BRT and BGT) against root-knot nematode M. incognita was confirmed by the pathogenicity test on tomato. These observations confirmed that F. oxysporumisolates possesses variability in pathogenicity ranging from pathogenic to bio-control agent. The plants inoculated with BRT isolate failed to show wilt symptoms while plants inoculated with BGT isolate showed wilt indices.  相似文献   
9.
This paper examines the development of aerobic granular sludge in the presence of a synthetic chelating agent, nitrilotriacetic acid (NTA), in sequencing batch reactors (SBR). The growth of seed sludge at 0.26 mM, 0.52 mM and 1.05 mM of NTA was found to be significantly lower as compared to that in the absence of NTA. Aerobic granulation was significantly enhanced in the three SBRs (R2, R3 and R4), which were fed with 0.26 mM, 0.52 mM and 1.05 mM of NTA as a co-substrate, in comparison to the acetate-alone fed SBR (R1). After 2 months of operation, the mean diameter of the biomass stabilized at 0.35 mm in R1 (acetate alone), as compared to 2.18 mm in R4 (1.05 mM NTA+acetate). NTA degradation was established in SBRs, with almost complete removal during the SBR cycle. Batch experiments also showed efficient degradation of NTA by the aerobic granules.  相似文献   
10.
The Air Quality Index (AQI) is an index for reporting daily air quality. A study on the annual and seasonal variations of Air Quality Index over a period of 9 years (1996-2004) based on daily averaged concentration data of criteria air pollutants has been conducted for Delhi. An attempt has been made to quantify the changes in the AQI on annual and seasonal (winter, summer, monsoon and post monsoon) basis for 9 years. Measurements for the seven monitoring sites (Nizamuddin, Ashok Vihar, Shahzada Baug, Shahadara, Janakpuri, Sirifort and ITO) in Delhi were analysed and trends were also compared amongst these sites. Maximum Operator Function method was used to compute the Air Quality Index of the above areas and percentage variations in different severity class is discussed which provides in depth analysis of the trends. The best air quality was depicted by Shahzada Baug followed by Shahdara, both of these were classified as industrial areas indicating that policy measures relating to the industries in the city during past years have helped in improving the air quality. The air quality in other areas have improved slightly in the span of nine years but still remains critical indicating continued rigorous efforts in this direction. Increased traffic density seems to have resulted into the worst air quality at ITO in the city amongst all the monitoring stations. There is a shift for the worst AQI in the city from winter to summer season in a time span of these nine years. Change of season for worst AQI from Winter to Summer may also be likely due to increased photochemical reactions playing major role with change in the nature of emissions imposed due to different control measures such as CNG implementation, significant shift to LPG in domestic sector etc. calling for a detailed study, those which started after the year 2000. After the year 2000, there is a significant increase in the Nitrogen-dioxide (NO(2)) concentration at all stations. ITO which has shown continuous exponential increase in pollution levels has first time showed a declining AQI trend in the year 2004 and one of the contributing factors could have been the Delhi metro (initiated in 2002) passing through congested neighbouring areas causing traffic decongestion here. In general, the areas which are farthest from metro route viz., Siri-fort, Nizamuddin, Janakpuri etc. did not record declining AQI in 2003 onwards as happened with stations closer to Metro route such as Ashok Vihar and ITO. An attempt has been made to quantify the reasons that lead to the changes in the values of the AQI.  相似文献   
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