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   1017篇
  免费   48篇
  国内免费   360篇
安全科学   49篇
废物处理   62篇
环保管理   65篇
综合类   571篇
基础理论   197篇
污染及防治   366篇
评价与监测   50篇
社会与环境   37篇
灾害及防治   28篇
  2023年   11篇
  2022年   57篇
  2021年   35篇
  2020年   25篇
  2019年   23篇
  2018年   28篇
  2017年   56篇
  2016年   59篇
  2015年   63篇
  2014年   75篇
  2013年   108篇
  2012年   97篇
  2011年   78篇
  2010年   54篇
  2009年   68篇
  2008年   90篇
  2007年   60篇
  2006年   71篇
  2005年   29篇
  2004年   24篇
  2003年   30篇
  2002年   28篇
  2001年   25篇
  2000年   26篇
  1999年   33篇
  1998年   26篇
  1997年   23篇
  1996年   19篇
  1995年   25篇
  1994年   11篇
  1993年   17篇
  1992年   18篇
  1991年   10篇
  1990年   6篇
  1989年   3篇
  1988年   5篇
  1987年   1篇
  1986年   1篇
  1985年   4篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
排序方式: 共有1425条查询结果,搜索用时 10 毫秒
31.
研究了用Fenton试剂处理选矿废水中残余的黄药,分别考查了氧化时间、反应初始pH值、Fe2+浓度及H2O2用量对黄药降解效果的影响,用正交试验确定了4个因素的最好条件。结果表明:初始pH值和H2O2用量是影响去除效果的主要因素;氧化时间为60 m in,反应初始pH=4,[Fe2+]=20 mg/L,[H2O2]=20 mg/L,黄药的浓度为125 mg/L时,黄药的去除率达到99.5%;初步探讨了Fenton试剂净化废水中黄药的机理是.OH自由基先将黄药氧化为过氧化黄原酸盐,再将其氧化为CO2,黄药得到去除。  相似文献   
32.
Samples of ambient air (including gaseous and particulate phases), dust fall, surface soil, rhizosphere soil, core (edible part), outer leaf, and root of cabbage from eight vegetable plots near a large coking manufacturer were collected during the harvest period. Concentrations, compositions, and distributions of parent PAHs in different samples were determined. Our results indicated that most of the parent PAHs in air occurred in the gaseous phase, dominated by low molecular weight (LMW) species with two to three rings. Specific isomeric ratios and principal component analysis were employed to preliminarily identify the local sources of parent PAHs emitted. The main emission sources of parent PAHs could be apportioned as a mixture of coal combustion, coking production, and traffic tailing gas. PAH components with two to four rings were prevailing in dust fall, surface soil, and rhizosphere soil. Concentrations of PAHs in surface soil exhibited a significant positive correlation with topsoil TOC fractions. Compositional profiles in outer leaf and core of cabbage, dominated by LMW species, were similar to those in the local air. Overall, the order of parent PAH concentration in cabbage was outer leaf > root > core. Partial correlation analysis and multivariate linear stepwise regression revealed that PAH concentrations in cabbage core were closely associated with PAHs present both in root and in outer leaf, namely, affected by adsorption, then absorption, and translocation of PAHs from rhizosphere soil and ambient air, respectively.  相似文献   
33.
灰霾的健康效应   总被引:57,自引:0,他引:57  
灰霾是颗粒物和气体污染物导致的可察觉到的能见度降低的污染天气现象.近年来,随着城市化进程的快速发展,城市大气污染加剧,灰霾天气也随之增多.总结了灰霾这一污染型天气的特征,介绍了灰霾的化学成分、污染机制等,并从影响机制和流行病学角度出发,对国内外灰霾对人体的健康效应研究成果进行了综合评述,提出目前急需解决的科学问题和今后的研究方向.  相似文献   
34.
Photocatalytic oxidation of triclosan   总被引:1,自引:0,他引:1  
Yu JC  Kwong TY  Luo Q  Cai Z 《Chemosphere》2006,65(3):390-399
In the spring of 2003, there was an outbreak of the severe respiratory syndrome (SARS) in Hong Kong. Health concerns have thus triggered an increased and predominant use of various types of household cleansing agents such as triclosan (5-chloro-2-(2,4-dichlorophenoxy)phenol). However, it has been reported recently that triclosan could be photochemically converted to toxic 2,8-dichlorodibenzo-p-dioxin (2,8-Cl(2)DD) in the environment. It is therefore necessary to develop environmentally friendly methods for the treatment of triclosan. To this end, photocatalytic degradation of triclosan in aqueous solution was conducted using TiO(2) (Degussa P25) under irradiation of UV light (lambda < 365 nm). It was found that triclosan could be degraded by this approach. Hydrogen peroxide was added to enhance the degradation process, and the optimal initial hydrogen peroxide concentration for triclosan degradation was 0.005% (w/v). Product identification indicated that triclosan oxidation occurred at its phenol moiety and yielded quinone and hydroquinone intermediates. The formation of a dichlorophenol intermediate in triclosan degradation suggested bond-breaking of the ether linkage occurred during the process. Moreover, no chlorinated dibenzo-p-dioxin congener was detected. These findings confirm that the photocatalytic degradation of triclosan is an environmentally friendly process.  相似文献   
35.
为了实现废弃棉织物的高效资源化利用,采用浓磷酸预处理,将棉纤维转化为葡萄糖,并回收高纯度涤纶.以磷酸浓度、磷酸与原料液固比、预处理温度和时间为研究对象,以涤纶回收纯度、葡萄糖收率为考察指标,采用中心组合设计(CCD),建立响应面模型对预处理工艺参数进行优化.并确定了最佳的浓磷酸预处理工艺条件为:磷酸质量分数85%,液固比15:1,预处理时间7 h,预处理温度50℃.在此条件下涤纶回收纯度可达100%,葡萄糖收率可达79.0%,且实验验证值与模型预测值较为接近,模型精度较高.此外,再生纤维素不经干燥直接酶水解,葡萄糖收率可被进一步提高至83.0%.  相似文献   
36.
针对增塑剂邻苯二甲酸二丁酯,邻苯二甲二辛酯的生产及废水治理现状,对生产过程的清洁生产审计及是提出清洁生产方案,并进行了实施,实施效果显著,污染物总量减少了85%产品生产所需原材料有所下降,不仅具有环保效益,同时也有一定的经济效益。  相似文献   
37.
蔡圣贤  朱锡恩  肖丙雁  徐正  王磊 《环境工程》2004,22(6):32-32,59
冷轧废水处理是轧钢工艺中的难点之一。宝钢 2 0 30冷轧废水处理改造工程 ,首次将生化处理技术引入到冷轧含油废水处理工艺 ,并在工程中采用了无机陶瓷超滤技术 ,从而实现了冷轧废水处理的国产化及国内技术总成  相似文献   
38.
The distribution of vascular plant species richness along an altitudinal gradient and their relationships with environmental variables, including slope, aspect, bank (flooding) height, and river width of the Xiangxi River, Hubei Province, were examined. Total vascular plant species richness changed with elevation: it increased at lower elevations, reached a maximum in the midreaches and decreased thereafter. In particular, tree and herbaceous species richness were related to altitude. Correlation analysis (Kendall's τ) between species richness and environmental variables indicated that the change in species richness in the riparian zone was determined by riparian environmental factors and characteristics of regional vegetation distribution along the altitudinal gradient. The low species richness at lower elevations resulted from seasonal flooding and human activities – agriculture and fuel collection – and the higher species richness in the midreaches reflected transitional zones in natural vegetation types that had had little disturbance. These results on species distribution in the riparian community could be utilized as a reference for restoration efforts to improve water quality of the emerging reservoir resulting from the Three Gorges Hydroelectric Dam project.  相似文献   
39.
This article examines the relationship between tourism, energy, and environment. This article approaches tourism as a complex adaptive system composed of consumers, transportation providers, travel intermediaries, and destinations composed of multiple tourism-related companies and other stakeholder groups. Environmental and energy-related challenges of components to the system are examined as well as various units – the system as a whole, enterprises and individuals – within the system. A total of 92 peer-reviewed articles were studied that address ‘energy’ and ‘tourism’ published between 1974 and 2011. Also addressed are the impacts of social and cultural differences between the United States and China concerning responses to environmental and energy-related challenges. This article concludes with recommendations for addressing the challenges associated with such challenges, including building system capacity, technology development and adoption, support of individual behavior change, increasing understanding of the trade-offs and interactions within the system, and adoption of multidisciplinary approaches to these challenges within the tourism system.  相似文献   
40.
Lead (Pb) is a well-studied environmental contaminant that has many negative health effects, especially for children. Both racial/ethnic and income disparities have been documented with respect to exposure to Pb in soils. The objectives of this study were to assess whether soil Pb concentrations in rural and urban areas of South Carolina USA, previously identified as having clusters of intellectual disabilities (ID) in children, were positively associated with populations of minority and low-income individuals and children (≤6 years of age). Surface soils from two rural and two urban areas with identified clusters of ID were analyzed for Pb and concentrations were spatially interpolated using inverse distance weighted analysis. Population race/ethnicity and income-to-poverty ratio (ITPR) from United States Census 2000 block group data were aerially interpolated by block group within each area. Urban areas had significantly higher concentrations of Pb than rural areas. Significant positive associations between black, non-Hispanic Latino, individuals and children ≤6 years of age and mean estimated Pb concentrations were observed in both urban (r = 0.38, p = 0.0007) and rural (r = 0.53, p = 0.04) areas. Significant positive associations also were observed between individuals and children with an ITPR < 1.00 and Pb concentrations, though primarily in urban areas. Racial/ethnic minorities and low ITPR individuals, including children, may be at elevated risk for exposure to Pb in soils.  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