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   1479篇
  免费   82篇
  国内免费   203篇
安全科学   102篇
废物处理   52篇
环保管理   427篇
综合类   689篇
基础理论   139篇
环境理论   5篇
污染及防治   93篇
评价与监测   43篇
社会与环境   205篇
灾害及防治   9篇
  2024年   3篇
  2023年   18篇
  2022年   27篇
  2021年   40篇
  2020年   51篇
  2019年   51篇
  2018年   42篇
  2017年   72篇
  2016年   80篇
  2015年   75篇
  2014年   71篇
  2013年   103篇
  2012年   126篇
  2011年   145篇
  2010年   91篇
  2009年   70篇
  2008年   77篇
  2007年   90篇
  2006年   78篇
  2005年   55篇
  2004年   53篇
  2003年   50篇
  2002年   43篇
  2001年   33篇
  2000年   24篇
  1999年   29篇
  1998年   16篇
  1997年   20篇
  1996年   15篇
  1995年   9篇
  1994年   5篇
  1993年   10篇
  1992年   6篇
  1991年   9篇
  1990年   5篇
  1989年   5篇
  1988年   6篇
  1987年   3篇
  1986年   3篇
  1984年   3篇
  1983年   3篇
  1982年   6篇
  1981年   7篇
  1980年   7篇
  1979年   3篇
  1978年   4篇
  1977年   5篇
  1973年   4篇
  1972年   3篇
  1971年   4篇
排序方式: 共有1764条查询结果,搜索用时 15 毫秒
101.
稠油火驱开采技术节能减排效果分析   总被引:3,自引:0,他引:3  
火驱作为稠油热采的有效接替技术,与注蒸汽开采技术相比,具有采收率高,能耗低,CO_2排放少的优势。文章从火驱驱油机理特征阐述了火驱与注蒸汽技术的不同点,从燃料开采能耗、热效率、注入剂资源、数据对比四个方面分析火驱比注蒸汽热效率高,无燃料开采成本,能耗是注蒸汽的50%;从CO_2气体排放方式和排放量对比可知,火驱能够减少温室气体排放,为油田节能减排、环保生产起到积极作用。  相似文献   
102.
A comprehensive study of various psychoactive substances and their metabolites was performed in the wastewater treatment plant of the city of Zagreb (780 000 inhabitants) using liquid chromatography/tandem mass spectrometry (LC-MS-MS). The estimation of drug abuse for five different illicit drugs, including heroin, cocaine, marijuana, amphetamine and ecstasy, was made on the basis of their representative excretion rates, which were determined over a period of 8 months. Marijuana (1000 kg/year), heroin (75 kg/year) and cocaine (47 kg/year) were found to be the most frequently consumed illicit drugs, while the consumption of amphetamine-type drugs was much lower (1-3 kg/year). A comparison with other reports indicated that drug abuse profiles in transition countries might be different from those reported for Western Europe, in particular with respect to the comparatively increased consumption of heroin. Enhanced consumption of stimulating drugs (cocaine and ectasy) was systematically detected during weekends.  相似文献   
103.
电力行业的节能减排与低碳经济   总被引:1,自引:0,他引:1  
中国能源结构以煤为主,火电行业是碳排放量的主体,面对低碳经济的发展模式,电力行业势必将成为CO2减排的主力军。目前,火电行业通过"上大压小"政策,实现结构减排;通过提高电力工业的烟气脱硫,实现工程减排;通过扩大清洁能源的比例,减少煤炭消耗总量,实现总量减排。使用清洁能源是实现碳减排的有效途径。指出了电力行业"节能减排"的现状和措施,分析了电力行业在"低碳经济"中所面临的新形势,并对低碳电力技术的研究与运用进行了展望,阐述了通过利用清洁能源促进碳减排的迫切性和必要性。  相似文献   
104.
House-Peters, Lily, Bethany Pratt, and Heejun Chang, 2010. Effects of Urban Spatial Structure, Sociodemographics, and Climate on Residential Water Consumption in Hillsboro, Oregon. Journal of the American Water Resources Association (JAWRA) 46(3):461-472. DOI: 10.1111/j.1752-1688.2009.00415.x Abstract: In the Portland metropolitan area, suburban growth in cities such as Hillsboro is projected to increase as people seek affordable housing near a burgeoning metropolis. The most significant determinants for increases in water demand are population growth, climate change, and the type of urban development that occurs. This study analyzes the spatial patterns of single family residential (SFR) water consumption in Hillsboro, Oregon, at the census block scale. The following research questions are addressed: (1) What are the significant determinants of SFR water consumption in Hillsboro, Oregon? (2) Is SFR water demand sensitive to drought conditions and interannual climate variation? (3) To what magnitude do particular census blocks react to drought conditions and interannual climate variation? Using ordinary least squares multiple regression and spatial regression methods, we found that base use, representing indoor water use, is dependent on household size and that seasonal use, representing external water use is dependent on both education level and the size of the property’s outdoor space. Spatial analysis techniques determined that although the water demand of the study area as a whole is not sensitive to drought conditions, certain individual census blocks do respond with a higher magnitude of water use. The most climate-sensitive census blocks tend to contain newer and larger homes, and have higher property values and more affluent and well-educated residents.  相似文献   
105.
为了考察水力停留时间(HRT)对炭纤维载体固定床厌氧反应器运行效果的影响,在进水COD分别为20 000~25 000 mg/L和40 000~45 000 mg/L2个浓度范围下,研究了不同HRT对反应器运行效果的影响。结果表明,通过HRT的调整,在达到相同有机负荷(OLR)下,进水COD为20 000~25 000 mg/L的COD去除率和产气量,明显比进水COD为40 000~45 000 mg/L的运行效果好;进水COD为20 000~25 000 mg/L,HRT为14 h,相应的OLR为41.09 kgCOD/(m3.d)时,COD去除率仍然维持在68%以上,沼气容积产气率达到14.55 m3/(m3.d)。炭纤维载体固定床厌氧反应器具有较高的COD去除率、产气效率以及抵抗低pH、高负荷冲击的能力,运行过程中没有发生反应器堵塞的现象。  相似文献   
106.
人口与消费对碳排放影响的分析模型与实证   总被引:22,自引:2,他引:20  
从消费压力人口视角探讨碳排放问题,有利于正确判断和把握气候变化压力的人文因素,以及人口与消费可持续发展的动力学机制.本文通过对STIRPAT模型的扩展,应用岭回归方法计量分析人口、消费及技术因素对碳排放的影响.对我国1980至2007年碳排放情况的统计实证结果表明,扩展的STIRPAT模型对中国国情有较高的解释力.居民消费水平、人口城市化率、人口规模三个因素对我国碳排放总量的变化影响明显;现阶段我国居民消费水平与人口结构变化对碳排放的影响力已高于人口规模变化的影响力,居民消费水平与消费模式等人文因素的变化有可能成为我国碳排放的新的增长点;技术进步因素在此模型中对我国该阶段碳排放的解释力有限,表明我国未来通过技术进步减缓碳排放的潜力巨大.  相似文献   
107.
中国现代城镇化发育的能源消费   总被引:2,自引:0,他引:2  
城镇是现代社会财富积累的中心。矿物燃料为主的一次能源不仅是现代人类社会发展的基本动力来源,也是现代城镇化发育的基本动力来源。随着城镇化发育不断走向成熟,城镇的生存和发展对能源消费的依赖日趋强烈。这种消费需求不仅体现在总量增长方面,而且更体现在质量提高方面。世界和中国的实践均证明了这一点。所不同者,在产业发展政策和能源消费政策的作用下,中国现代城镇化发育的能源消费表现出明显的不尽人意:第一,能源消费总量增长迅速,甚至进入21世纪以来也是如此;第二,能源消费结构演进缓慢、特别是进入国家城镇化快速发育阶段后的表现更是如此;第三,能源产出效率提高有限,甚至出现一定程度的倒退。如此能源消费特征,对中国城镇化的持续发育构成了巨大挑战,因此,建议加快城镇产业结构调整、推进能源消费结构演进和提高城镇能源消费质量。  相似文献   
108.
江苏省能源可持续发展模式初探   总被引:1,自引:0,他引:1  
针对目前江苏省能源可持续发展面临的挑战,以保障江苏能源综合供需平衡和实现能源 经济 环境协调发展为目标,以调整能源结构、优化能源供给体系、提高能源转化效率和清洁性为立足点,以充分利用省内不同区位的能源发展优势为主线,因地制宜地提炼出江苏省能源可持续发展的基本模式,包括自有资源优化开发模式和外部资源导入开发模式两大类型。其中,自有资源优化开发模式又可分为徐州煤炭工业综合体、苏北石油工业基地和沿海滩涂型可再生能源基地3种子模式;外部资源导入开发模式可分为沿江电力生产基地、苏南电力负荷中心和沿海临港型能源基地3种子模式。各种模式协同发展,有利于增强江苏省的能源可持续发展能力.  相似文献   
109.
In this research, toxicological safety of two newly developed methods for the treatment of landfill leachate from the Piškornica (Croatia) sanitary landfill was investigated. Chemical treatment procedure combined chemical precipitation with CaO followed by coagulation with ferric chloride and final adsorption by clinoptilolite. Electrochemical treatment approach included pretreatment with ozone followed by electrooxidation/electrocoagulation and final polishing by microwave irradiation. Cell viability of untreated/treated landfill leachate was examined using fluorescence microscopy. Cytotoxic effect of the original leachate was obtained for both exposure periods (4 and 24 h) while treated samples showed no cytotoxic effect even after prolonged exposure time. The potential DNA damage of the untreated/treated landfill leachate was evaluated by the comet assay and cytokinesis-block micronucleus (CBMN) assay using either human or plant cells. The original leachate exhibited significantly higher comet assay parameters compared to negative control after 24 h exposure. On the contrary, there was no significant difference between negative control and chemically/electrochemically treated leachate for any of the parameters tested. There was also no significant increase in either CBMN assay parameter compared to the negative control following the exposure of the lymphocytes to the chemically or electrochemically treated landfill leachate for both exposure periods while the original sample showed significantly higher number of micronuclei, nucleoplasmic bridges and nuclear buds for both exposure times. Results suggest that both methods are suitable for the treatment of such complex waste effluent due to high removal efficiency of all measured parameters and toxicological safety of the treated effluent.  相似文献   
110.
Contaminated food through dietary intake has become the main potential risk impacts on human health. This study investigated concentrations of rare earth elements (REEs) in soil, vegetables, human hair and blood, and assessed human health risk through vegetables consumption in the vicinity of a large-scale mining area located in Hetian Town of Changting County, Fujian Province, Southeast China. The results of the study included the following mean concentrations for total and bio-available REEs of 242.92 ± 68.98 (135.85–327.56) μg g−1 and 118.59 ± 38.49 (57.89–158.96) μg g−1 dry weight (dw) in agricultural soil, respectively, and total REEs of 3.58 ± 5.28 (0.07–64.42) μg g−1 dw in vegetable samples. Concentrations of total REEs in blood and hair collected from the local residents ranged from 424.76 to 1274.80 μg L−1 with an average of 689.74 ± 254.25 μg L−1 and from 0.06 to 1.59 μg g−1 with an average of 0.48 ± 0.59 μg g−1 of the study, respectively. In addition, a significant correlation was observed between REEs in blood and corresponding soil samples (R2 = 0.6556, p < 0.05), however there was no correlation between REEs in hair and corresponding soils (p > 0.05). Mean concentrations of REEs of 2.85 (0.59–10.24) μg L−1 in well water from the local households was 53-fold than that in the drinking water of Fuzhou city (0.054 μg L−1). The health risk assessment indicated that vegetable consumption would not result in exceeding the safe values of estimate daily intake (EDI) REEs (100−110 μg kg−1 d−1) for adults and children, but attention should be paid to monitoring human beings health in such rare earth mining areas due to long-term exposure to high dose REEs from food consumptions.  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