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   341篇
  免费   13篇
  国内免费   7篇
安全科学   28篇
废物处理   15篇
环保管理   77篇
综合类   34篇
基础理论   84篇
污染及防治   62篇
评价与监测   41篇
社会与环境   18篇
灾害及防治   2篇
  2023年   1篇
  2022年   1篇
  2021年   4篇
  2020年   2篇
  2019年   5篇
  2018年   9篇
  2017年   8篇
  2016年   24篇
  2015年   9篇
  2014年   11篇
  2013年   26篇
  2012年   10篇
  2011年   18篇
  2010年   15篇
  2009年   23篇
  2008年   15篇
  2007年   23篇
  2006年   15篇
  2005年   14篇
  2004年   26篇
  2003年   21篇
  2002年   11篇
  2001年   10篇
  2000年   4篇
  1999年   2篇
  1998年   2篇
  1997年   3篇
  1996年   6篇
  1995年   5篇
  1994年   3篇
  1993年   2篇
  1992年   1篇
  1991年   3篇
  1990年   1篇
  1989年   4篇
  1988年   4篇
  1986年   3篇
  1984年   2篇
  1983年   1篇
  1982年   5篇
  1981年   2篇
  1979年   3篇
  1977年   2篇
  1973年   2篇
排序方式: 共有361条查询结果,搜索用时 8 毫秒
121.
Field experiments were carried out in the vicinity of anisolated building using open-path and point monitoring airpollution detectors to measure concentrations of a tracer gasreleased from a source located either on the building or at thedownwind face of the building. Experiments were conducted underneutral or slightly unstable weather conditions. Either threeor five fast-response point monitors were located along thebeam path of an open-path instrument, in the wake of thebuilding. Experiments were performed with different sourcelocations, detector locations and building orientations to thewind. Visual comparison of data time series showed that datafrom the two types of instruments followed similar trends. Thebest degree of correlation occurred for an averaging timesimilar to the response time of the open-path monitor. Meanconcentrations detected by the open-path instrument weregenerally in very good agreement with the path averaged meanconcentrations from the point monitors. The point monitors werealso capable of providing time-resolved data needed to describedetailed concentration fluctuation statistics.  相似文献   
122.
The effects of maize (Zea mays L.), genetically modified to express the Cry1Ab protein (Bt), and an insecticide on soil microbial and faunal communities were assessed in a glasshouse experiment. Soil for the experiment was taken from field sites where the same maize cultivars were grown to allow comparison between results under glasshouse conditions with those from field trials. Plants were grown in contrasting sandy loam and clay loam soils, half were sprayed with a pyrethroid insecticide (deltamethrin) and soil samples taken at the five-leaf stage, flowering, and maturity. The main effect on all measured parameters was that of soil type and there were no effects of Bt trait or insecticide on plant growth. The Bt trait resulted in more soil nematodes and protozoa (amoebae), whereas insecticide application increased plant Bt concentration and altered nematode community structure. The only significant effects on soil microbial community structure, microarthropods, and larvae of a nontarget root-feeding Dipteran, were due to soil type and plant growth stage. The results indicate that, although there were statistically significant effects of the Bt trait on soil populations, they were small. The relative magnitude of the effect could best be judged by comparison with the insecticide treatment, which was representative of current best practice. The Bt trait had no greater effect than the insecticide treatment. Results from this glasshouse experiment were in broad agreement with conclusions from field experiments using the same plant material grown in the same soils.  相似文献   
123.
Environment, Development and Sustainability - The use of wastes for biogas production has been restricted to few feedstock like cattle manure and food waste. Increasing the feedstock base for...  相似文献   
124.
A dry deposition model (RDM) for operational application has beenevaluated and modified in the present study. Field measurements of friction velocity and dry deposition velocity of SO2 andO3 over a mixed forest have been used to evaluate RDM. It was found that RDM predicts friction velocities very close to measurements and thus it can predict reasonable aerodynamic resistance. RDM overestimated O3 deposition during dry nighttime conditions and underestimated both O3 andSO2deposition for early morning hours. It could not predict the mean diurnal variation in deposition velocity for either O3 or SO2 deposition under wet surface conditions. Modifications have been made for O3 and SO2 dry deposition based on the comparison of results and based upon additional published data. Compared to an earlier version of RDM, the modified versionpredicts better results for O3 and SO2 dry deposition,especially under rain and dew conditions.  相似文献   
125.
Captive breeding and reintroduction remain high profile but controversial conservation interventions. It is important to understand how such programs develop and respond to strategic conservation initiatives. We analyzed the contribution to conservation made by amphibian captive breeding and reintroduction since the launch of the International Union for Conservation of Nature (IUCN) Amphibian Conservation Action Plan (ACAP) in 2007. We assembled data on amphibian captive breeding and reintroduction from a variety of sources including the Amphibian Ark database and the IUCN Red List. We also carried out systematic searches of Web of Science, JSTOR, and Google Scholar for relevant literature. Relative to data collected from 1966 to 2006, the number of species involved in captive breeding and reintroduction projects increased by 57% in the 7 years since release of the ACAP. However, there have been relatively few new reintroductions over this period; most programs have focused on securing captive‐assurance populations (i.e., species taken into captivity as a precaution against extinctions in the wild) and conservation‐related research. There has been a shift to a broader representation of frogs, salamanders, and caecilians within programs and an increasing emphasis on threatened species. There has been a relative increase of species in programs from Central and South America and the Caribbean, where amphibian biodiversity is high. About half of the programs involve zoos and aquaria with a similar proportion represented in specialist facilities run by governmental or nongovernmental agencies. Despite successful reintroduction often being regarded as the ultimate milestone for such programs, the irreversibility of many current threats to amphibians may make this an impractical goal. Instead, research on captive assurance populations may be needed to develop imaginative solutions to enable amphibians to survive alongside current, emerging, and future threats.  相似文献   
126.
Facilitating disaster preparedness through local radio broadcasting   总被引:1,自引:0,他引:1  
Romo-Murphy E  James R  Adams M 《Disasters》2011,35(4):801-815
The 2008 Disaster Mitigation Preparedness (DMP) study took place in Aceh province, Indonesia. It sought to help develop radio programmes and messages to increase resilience to disasters. The role of radio was evaluated during and after the 2004 Asian tsunami disaster. The study team interviewed 984 tsunami survivors from nine sub-districts of Banda Aceh, and local nongovernmental organisations convened eight focus groups around the area of Aceh Besar. Six key informant interviews were held with government disaster management agencies. The DMP survey is the first of its kind to interview a representative random sample of Banda Aceh residents. It reveals the importance of community and social networks, during disaster situations, when essential communications are down. A disaster warning information system based on a multi-media approach needs to be developed. The wider community should be involved in the planning, education and training of Banda Aceh and Aceh Besar residents to facilitate appropriate personal and community survival strategies.  相似文献   
127.
128.
Various governmental regulatory agencies are responsible for establishing regulations on the discharge of chlorinated organic compounds from pulp and paper mills. The procedures for setting permit limits are the basic topic of this article. Different methods of determining permit limits are set forth and discussed in a number of references, including documents of the Environmental Protection Agency. This paper discusses in detail the application of one particular methodology—the lognormal model approach. In this paper we utilize a real data set and include the necessary calculations required to set up permit limits. The basic tenets of the permit process are such that if limits are set too low, operators who are in full regulatory compliance will still be frequently cited, and if limits are set too high, operators who are not in compliance will seldom if ever be cited. Thus there is a great need for these effluent limits to be determined with great care, both to protect the environment receiving the wastewater and the industry producing the wastewater.  相似文献   
129.
130.
Species Reintroductions   总被引:1,自引:0,他引:1  
  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