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   324篇
  免费   27篇
  国内免费   113篇
安全科学   35篇
废物处理   23篇
环保管理   17篇
综合类   205篇
基础理论   70篇
污染及防治   68篇
评价与监测   29篇
社会与环境   12篇
灾害及防治   5篇
  2024年   4篇
  2023年   6篇
  2022年   24篇
  2021年   21篇
  2020年   29篇
  2019年   9篇
  2018年   15篇
  2017年   17篇
  2016年   14篇
  2015年   13篇
  2014年   16篇
  2013年   26篇
  2012年   23篇
  2011年   33篇
  2010年   28篇
  2009年   24篇
  2008年   29篇
  2007年   14篇
  2006年   10篇
  2005年   11篇
  2004年   12篇
  2003年   10篇
  2002年   15篇
  2001年   17篇
  2000年   10篇
  1999年   9篇
  1998年   6篇
  1997年   3篇
  1996年   9篇
  1995年   2篇
  1994年   1篇
  1993年   3篇
  1987年   1篇
排序方式: 共有464条查询结果,搜索用时 15 毫秒
101.
To ensure the safety of drinking water, ozone (O3) has been extensively applied in drinking water treatment plants to further remove natural organic matter (NOM). However, the surface water and groundwater near the coastal areas often contain high concentrations of bromide ion (Br?). Considering the risk of bromate (BrO3?) formation in ozonation of the sand-filtered water, the inhibitory efficiencies of hydrogen peroxide (H2O2) and ammonia (NH3) on BrO3? formation during ozonation process were compared. The addition of H2O2 effectively inhibited BrO3? formation at an initial Br? concentration amended to 350 µg/L. The inhibition efficiencies reached 59.6 and 100% when the mass ratio of H2O2/O3 was 0.25 and > 0.5, respectively. The UV254 and total organic carbon (TOC) also decreased after adding H2O2, while the formation potential of trihalomethanes (THMsFP) increased especially in subsequent chlorination process at a low dose of H2O2. To control the formation of both BrO3? and THMs, a relatively large dose of O3 and a high ratio of H2O2/O3were generally needed. NH3 addition inhibited BrO3? formation when the background ammonia nitrogen (NH3N) concentration was low. There was no significant correlation between BrO3? inhibition efficiency and NH3 dose, and a small amount of NH3N (0.2 mg/L) could obviously inhibit BrO3? formation. The oxidation of NOM seemed unaffected by NH3 addition, and the structure of NOM reflected by synchronous fluorescence (SF) scanning remained almost unchanged before and after adding NH3. Considering the formation of BrO3? and THMs, the optimal dose of NH3 was suggested to be 0.5 mg/L.  相似文献   
102.
黑岱沟露天煤矿排土场果园景观生态建设研究   总被引:2,自引:0,他引:2  
本文通过对黑岱沟露天煤矿开发所形成新的人工环境条件下的气候和土壤等因子分析,应用景观生态学原理,规划建设了以观赏为主的果园观生态建设。通过对所载植果树和其它乔灌木的观测研究,筛选出了适宜于排土场生长的杏树、苹果梨、123苹果、山桃等果树品种,以及油松、旱柳、榆树、沙棘、玫瑰和先辈乔灌木品种,完成了排土场的景观生态建设工作,为矿区大面积土地复垦提供了依据。  相似文献   
103.
通过对扬州市危险废弃物环境管理现状的分析,提出了加强危险废物环境管理的几点措施.  相似文献   
104.
Chiang PN  Wang MK  Chiu CY  King HB  Hwong JL 《Chemosphere》2004,54(2):217-224
The carbon isotope analysis [delta13C values] of organic samples can be a useful research in ecological studies because delta13C values are indicative of the plant source. This study investigated the changes in plant communities along the grassland-forest boundary in the alpine forest at Ta-Ta-Chia long term ecological research (LTER) site in central Taiwan using carbon isotope data. The aim of this study was focused on the forest fire affected the change of vegetation community. Four pedons from grassland dominated by Miscanthus transmorrisonensis (pedons 1 and 2), transition zone by Tsuga and Yushania nittakeyamensis (pedon 3), and forest zone by Tsuga and nittakeyamensis (pedon 4) were examined. Soil organic matter (SOM) delta13C values in the upper soil horizon were similar to delta13C values of the overlaying vegetation types. This indicates that the boundary between these plant communities remained the same in the past decades. The delta13C values of the grassland SOM ranged from -19.4 per thousand to -24.1 per thousand, showing decrease with soil depth. This suggests that C4 plants (transmorrisonensis) have replaced C3 plants of Tsuga and nittakeyamensis. The delta13C values of the Tsuga forest area (pedon 4) range from -27.0 per thousand to -23.5 per thousand and showed only slight change with soil depth, implying that C3 plants have remained the major species in the forest.  相似文献   
105.
11种取代酚类内分泌干扰活性的初步筛选与评价   总被引:10,自引:2,他引:10  
通过聚蔗糖-泛影葡胺密度梯度离心法,从鲫鱼(Carassius auratus)外周血中分离出淋巴细胞,体外培养24h,用MTT法测试双酚类、联苯酚类、二酚类、烷基单酚类和取代酚类等几类可疑环境内分泌干扰物对淋巴细胞增殖的影响.结果表明,双酚类、联苯酚类和烷基单酚类物质对鲫鱼淋巴细胞的增殖具有低浓度促进,高浓度抑制的作用.二酚类物质对鲫鱼淋巴细胞的增殖具有促进作用.取代酚类对鲫鱼淋巴细胞的增殖无明显作用.该结果表明,此方法可以对环境内分泌干扰物进行初步筛选,同时发现环境内分泌干扰物对淋巴细胞增殖的效应与物质的化学结构具有一定相关性。  相似文献   
106.
分析中国西部地区生态环境的主要问题及其生态环境建设在中国的战略地位,指出西部地区应建立环境与经济相互协调,互相促进的生态经济体系。并从技术结构层面和政策层面对西部地区生态经济系统的建立提出一些新的想法与建议。  相似文献   
107.
用上流式厌氧污泥床处理味精废水的研究   总被引:4,自引:0,他引:4  
采用了上流式厌氧污泥床处理高浓度味精废水 ,研究了UASB反应器的菌种培养驯化条件和连续运行工艺参数 ,并分析了不同操作条件下去除废水中COD的效果  相似文献   
108.
Seven kinds of heavy metal accumulation of rubbish compost in turfgrass by EDTA chelating were investigated. With EDTA application, heavy metal accumulation by two species of turfgrass was increased significantly. The enrichment coefficients of Lolium perenne L(L) and Festuca arundinacea L(F) to Cr reached 9.45 and 6.15 respectively. In the range of EDTA dosages given, heavy metal accumulation in turfgrass increased with increasing EDTA level. There were significant differences in remediation of different metals by applying EDTA. L had high ability to accumulate Cr, Cd, Ni and Zn, showing better remediation to heavy metals of rubbish compost.In contrast, F showed high ability to accumulate Cr, Ni, Cu and Zn. Low EDTA level increased aboveground net primary production (ANP) of turfgrass, but EDTA would considerably inhibit it when EDTA was higher than 20 mmol/kg. The results demonstrated that the optimum dosage of EDTA for remediating heavy metals in rubbish compost by turfgrass was between 10 mmol/kg and 20 mmol/kg.  相似文献   
109.
Over the past decade, the emission standards and fuel standards in Beijing have been upgraded twice, and the vehicle structure has been improved by accelerating the elimination of 2.95 million old vehicles. Through the formulation and implementation of these policies, the emissions of carbon monoxide (CO), volatile organic compounds (VOCs), nitrogen oxides (NOx), and fine particulate matter (PM2.5) in 2019 were 147.9, 25.3, 43.4, and 0.91 kton in Beijing, respectively. The emission factor method was adopted to better understand the emissions characteristics of primary air pollutants from combustion engine vehicles and to improve pollution control. In combination with the air quality improvement goals and the status of social and economic development during the 14th Five-Year Plan period in Beijing, different vehicle pollution control scenarios were established, and emissions reductions were projected. The results show that the emissions of four air pollutants (CO, VOCs, NOx, and PM2.5) from vehicles in Beijing decreased by an average of 68% in 2019, compared to their levels in 2009. The contribution of NOx emissions from diesel vehicles increased from 35% in 2009 to 56% in 2019, which indicated that clean and energy-saving diesel vehicle fleets should be further improved. Electric vehicle adoption could be an important measure to reduce pollutant emissions. With the further upgrading of vehicle structure and the adoption of electric vehicles, it is expected that the total emissions of the four vehicle pollutants can be reduced by 20%-41% by the end of the 14th Five-Year Plan period.  相似文献   
110.
人工甜味剂(ASs)作为一类新兴污染物在世界范围内的各种水体中被广泛检出,本文选取具有代表性的糖精(SAC)作为研究对象,探讨了紫外/过氧化氢(UV/H2O2)和UV/过硫酸盐(PS)两种高级氧化工艺(AOPs)降解SAC的动力学、影响因素、矿化率、转化产物和降解机制.结果表明:单独的UV、PS和H2O2对SAC的去除效果有限(去除率<5%),UV/H2O2和UV/PS工艺对SAC的去除效果良好(去除率>99%)且降解符合伪一阶动力学,速率分别为0.38 min-1和0.09 min-1.降低溶液pH值、增大PS浓度均可促进SAC降解;但随着H2O2浓度的升高,SAC降解效率先增加后减小.相比UV/PS工艺,UV/H2O2工艺降解SAC的矿化率更高(可达43%).产物鉴定结果表明,两种UV-AOPs氧化降解SAC均会生成开环产物,表明反应会破坏SAC分子中的N—S结构.此外,UV/H2O2工艺更易生成羟基化产物,二聚体产物仅在UV/PS工艺中被检测到.  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