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   313篇
  免费   22篇
  国内免费   88篇
安全科学   26篇
废物处理   17篇
环保管理   23篇
综合类   188篇
基础理论   67篇
污染及防治   74篇
评价与监测   13篇
社会与环境   12篇
灾害及防治   3篇
  2023年   8篇
  2022年   20篇
  2021年   21篇
  2020年   17篇
  2019年   11篇
  2018年   17篇
  2017年   17篇
  2016年   10篇
  2015年   14篇
  2014年   24篇
  2013年   30篇
  2012年   23篇
  2011年   31篇
  2010年   10篇
  2009年   26篇
  2008年   22篇
  2007年   19篇
  2006年   10篇
  2005年   9篇
  2004年   10篇
  2003年   4篇
  2002年   7篇
  2001年   5篇
  2000年   10篇
  1999年   11篇
  1998年   7篇
  1997年   1篇
  1996年   5篇
  1995年   7篇
  1994年   8篇
  1993年   3篇
  1992年   1篇
  1990年   1篇
  1989年   2篇
  1988年   2篇
排序方式: 共有423条查询结果,搜索用时 250 毫秒
91.
ConcentrationlevelofheavymetalsintheGreatWallBay,Antarcticainaustralsummer¥PuJiabin;FuYunna;LiZhongping(InstituteofMarineEnvi...  相似文献   
92.
就长江,嘉陵江重庆干流段和城区段污染物的来源以及估算污染负荷的方法进行了详细地介绍,给出各类污染源生产的污染负荷,并进行了分析比较,提出了今后重庆控制的污染物和污染源。  相似文献   
93.
Ten male buffalo calves were randomly allotted into five groups of two each. Four groups were fed with cadmium, molybdenum, cadmium-molybdenum, and copper-cadmium-molybdenum respectively for 130 days to determine the elements' metabolic interactions in calves. These results indicated that cadmium and molybdenum could increase the accumulation of molybdenum and cadmium in liver and kidneys in buffalo calves, but copper could not. reduce to normal the levels of molybdenum and cadmium in liver and kidneys caused by cadmium-molybdenum. In addition, we found the copper concentrations in liver and kindeys was significantly greater in treatment calves than in controls.  相似文献   
94.
碱矿渣水泥基铬渣固化体的性能研究   总被引:11,自引:0,他引:11  
使用碱矿渣水泥基材料对含铬废渣进行了固化研究,并力图使固化体能够用作建材制品。结果表明,用碱矿渣水泥基材固化铬渣是可行的,固化体抗压强度达到了50MPa以上,且具有良好的抗渗性能和较低的六价铬离子浸出率,能够用作建筑材料。  相似文献   
95.
对筛选的自生固氮菌和纤维素分解菌进行混合培养,研究了菌数与菌液含氮量的变化情况.初步探索了在两种菌混合作用下对生活垃圾的分解作用及增肥效应的影响。实验证明:两种菌在一定情况下能相互利用、相互依存,经混合培养后发酵液的含氮量增高,菌数增加。在两种菌液混合作用下可以加速生活垃圾的降解,同时提高其含氮量,且含有大量的具有生物活性的固氮菌和纤维素分解菌,可作为生物活性有机肥料。  相似文献   
96.
With increasing emission of silver nanoparticles (AgNPs) into the environment, it is important to understand the effects of ambient concentration of AgNPs. The biological effects of AgNPs on Scenedesmus obliquus, a ubiquitous freshwater microalgae, was evaluated. AgNPs exerted a minor inhibitory effect at low doses. Non-targeted metabolomic studies were conducted to understand and analyze the effect of AgNPs on algal cells from a molecular perspective. During the 48?hr of exposure to AgNPs, 30 metabolites were identified, of which nine had significant changes compared to the control group. These include d-galactose, sucrose, and d-fructose. These carbohydrates are involved in the synthesis and repair of cell walls. Glycine, an important constituent amino acid of glutathione, increased with AgNP exposure concentration increasing, likely to counteract an increased intracellular oxidative stress. These results provide a new understanding of the toxicity effects and mechanism of AgNPs. These metabolites could be useful biomarkers for future research, employed in the early detection of environmental risk from AgNPs.  相似文献   
97.
微生物法烟气脱硫技术研究   总被引:34,自引:0,他引:34  
采用微生物(氧化亚铁硫杆菌,简称TF菌)法脱除烟气中的二氧化硫。在相同操作条件下,比较了传统的工业化 方法稀硫酸吸收法(千代田法)与本法的优劣,研究了液气化、二氧化硫浓度、三价铁离子浓度等因素对吸收效率的影响;分析了脱硫反应前后吸收率pH值、三价铁离子浓度的变化。研究结果表明:适宜的液气比(12.5L/Nm^3 以上)、二氧化硫浓度(1000-5000ppm)和三价铁离子浓度(0.6g/L以上)能使该法具有较高(>98%)的脱硫率。在常温常压操作条件下,微生物法的脱硫率远优于千代田法,具有一定的工业化价值。  相似文献   
98.
本文计对三峡库区紫色丘陵地区的土壤生态环境状况,提出了优化评价的总目标、评价指标体系和评价程序,探讨了单项指数评价方法的数学模型与基准参数,在此基础上,应用了层次分析与模糊数学的原理和方法,对紫色土生态优化进行综合评价,旨在为库区及库周生态与环境建设及经济综合开发提供依据。  相似文献   
99.
Environmental impact assessment (EIA) system has been established in China since 1973. In present EIA cases, there are four participants in general: governments, enterprises, EIA organizations and the public. The public has held responsible for both social costs and social duties. The public supervises social costs produced by enterprises discharging pollutant in EIA. However public participation is mostly deputized by governments, which severely weaken the independence of the public as one participant in EIA. In this paper, EIA refers to the different attitudes of the participants whose optional strategies may be described by a proper game model. According to disfigurements in EIA, three sides (governments, enterprises, and EIA organizations) dynamic iterative game theory, dynamic game theory of incomplete information, and perfect Bayesian equilibrium theory to analyze the reciprocity relation among governments, EIA organizations and enterprises. The results show that in a short period, economic benefit is preponderant over social benefit. Governments and enterprises both do not want to take EIA to reveal social costs. EIA organizations’ income comes from enterprises and the collusions are built between them to vindicate economic benefit. In a long run, social benefit loss caused by environmental pollution must be recuperated sooner or later and environmental deterioration will influence the achievements of economic benefit, so both governments and enterprises are certain to pursue high social benefit and willing to take EIA, helpful to increase private benefit. EIA organizations will make fair assessment when their economic benefit are ensured. At present, the public as silent victims can not take actual part in EIA. The EIA system must be improved to break the present equilibrium of three sides, bringing the public to the equilibrium to exert public supervision.  相似文献   
100.
Ethanol–gasoline-blended fuel was tested in a conventional engine under various air–fuel equivalence ratios (λ) for its performance and emissions. The amount of fuel injection was adjusted manually by an open-loop control system using a CONSULT controller. It was found that without changing throttle opening and injection strategy, λ could be extended to a leaner condition as ethanol content increased. The results of engine performance tests showed that torque output would increase slightly at small throttle valve opening when ethanol–gasoline-blended fuel was used. It was also shown that CO and HC emissions were reduced with the increase of ethanol content in the blended fuel, which resulted from oxygen enrichment. At an air–fuel equivalence ratio slightly larger than one, the smallest amounts of CO and HC and the largest amounts of CO2 resulted. It was noted that under the lean combustion condition, CO2 emission was controlled by air–fuel equivalence ratio; while under the rich combustion condition, CO2 emission is offset by CO emission. It was also found that CO2 emission per unit horse power output for blended fuel was similar or less than that for gasoline fuel. From the experimental data, the optimal ethanol content in the gasoline and air–fuel equivalence ratio in terms of engine performance and air pollution was found.  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