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   971篇
  免费   71篇
  国内免费   307篇
安全科学   65篇
废物处理   75篇
环保管理   71篇
综合类   530篇
基础理论   217篇
污染及防治   281篇
评价与监测   35篇
社会与环境   37篇
灾害及防治   38篇
  2024年   2篇
  2023年   20篇
  2022年   55篇
  2021年   39篇
  2020年   41篇
  2019年   38篇
  2018年   36篇
  2017年   49篇
  2016年   49篇
  2015年   46篇
  2014年   82篇
  2013年   87篇
  2012年   85篇
  2011年   75篇
  2010年   68篇
  2009年   68篇
  2008年   44篇
  2007年   50篇
  2006年   33篇
  2005年   31篇
  2004年   32篇
  2003年   32篇
  2002年   37篇
  2001年   24篇
  2000年   30篇
  1999年   33篇
  1998年   41篇
  1997年   23篇
  1996年   17篇
  1995年   21篇
  1994年   13篇
  1993年   6篇
  1992年   8篇
  1991年   9篇
  1990年   6篇
  1988年   2篇
  1987年   1篇
  1986年   4篇
  1985年   2篇
  1984年   2篇
  1983年   1篇
  1982年   1篇
  1981年   3篇
  1977年   2篇
  1969年   1篇
排序方式: 共有1349条查询结果,搜索用时 687 毫秒
861.
Ambient air quality standards are the core strategic goal of ambient air quality management. Countries worldwide have given importance to research on the development of ambient air quality standards. To understand the history of the development of China's ambient air quality standards, this study analyzed the background associated with all previous formulations and revisions of the standards, classification of functional areas, standard grading, pollutants, and evolution of the standard limits over the past 40 years. The results show that since the initial release of the “Ambient Air Quality Standard” by China in 1982, it has been supplemented once, revised twice, and modified twice. The first ambient air quality standard specified the standard limits of six pollutants commonly found in ambient air. With the development of ambient air quality management, the number of pollutants has increased to ten. Since the release of the “Ambient Air Quality Standards” in 2012, the ambient air quality in China has significantly improved. However, the proportion of cities meeting these standards is still low. At present, China is suitably positioned to make the standards associated with 24 hr SO2 concentrations more stringent such that it meets the values defined in the World Health Organization (WHO) interim target-2 and the WHO air quality guideline (AQG). We further suggested that the SO2 standard should be revised promptly. Simultaneously, regions with a relatively high proportion of cities meeting the standard are encouraged to introduce more stringent interim target limits in due course to manage the local ambient air quality.  相似文献   
862.
Environmental Science and Pollution Research - Pavement surface temperature is of great significance to pavement performance and pavement design, as well as the development of cool pavements. The...  相似文献   
863.
Environmental Science and Pollution Research - Poor agricultural communities are particularly more disruptive to changes in climate. In southeast Asian countries, Pakistan is extremely vulnerable...  相似文献   
864.
Restoration processes of pollution zones in Hanjiang River   总被引:1,自引:1,他引:1  
RestorationprocessesofpollutionzonesinHanjiangRiver¥ShenYunfen;TanYuyun;FengWeisong;GuManru(InstituteofHydrobiology,ChineseAc...  相似文献   
865.
Fungi exposure has been linked to asthma and allergies among children. To determine the association between fungal exposure and wheeze and rhinitis symptoms, we examined concentrations of culturable indoor and outdoor fungi of various aerodynamic sizes in low and high allergic prevalence child care centers (CCCs) in Singapore. Environmental parameters were also performed for air temperature, relative humidity and ventilation rates, while information on CCC characteristics was collected via an inspection. Most commonly recovered fungi were Penicillium, Aspergillus, Geotrichum, Cladosporium and sterile mycelia with Geotrichum and sterile mycelia amounting to an average of 71.5% of the total airborne culturable fungi studied. Indoor and outdoor total culturable fungi concentrations and those in the size range of 1.1–3.3 μm were significantly higher in high allergic prevalence CCCs. When fungal types/genera were compared, indoor and outdoor Geotrichum and sterile mycelia of aerodynamic sizes 1.1–3.3 μm were found to be significantly elevated in high allergic prevalence CCCs. Indeed, average geometric mean diameters (Dg, ave) of indoor and outdoor culturable fungi were consistently smaller in CCCs with high prevalence of allergies than those with low prevalence. We found significant associations of higher fungal concentrations, especially those with smaller aerodynamic sizes in CCCs situated near parks. There were no differences in fungal levels between CCCs with respect to their dampness profile mainly due to high CCC ventilation rates. Since particle size is a factor that determines where a fungi particle deposits in the respiratory tract, this study provides useful information in the etiology of wheeze and rhinitis symptoms among the CCC attending children.  相似文献   
866.
The study examined the effects of situational (store busyness and customer demand) and dispositional (extraversion, neuroticism, and psychoticism) factors on the display of positive emotions. We found that for situational factors, customer demand was positively related to displayed positive emotions. For personality factors, extraversion was positively related to displayed positive emotions and neuroticism was negatively related to displayed positive emotions. Usefulness analysis showed that both situational and personality factors contributed significantly to explain the level of positive displayed emotion. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
867.
结合河北省桃园农药厂开发的百草枯新工艺(低温钠法),对百草枯生产过程中的环境风险进行评价。首先介绍了百草枯生产的工艺流程,然后系统分析了金属钠、吡啶、氯甲烷以及百草枯等危险物的性质及其危害性,并在上述分析的基础上,采用相应的评价模型对钠化釜及合成釜中吡啶可能造成的爆炸与扩散进行了评价。最后,就百草枯生产的环境风险提出了相应的对策和防范措施。  相似文献   
868.
电化学法消毒处理医院污水的试验研究   总被引:1,自引:0,他引:1  
采用电化学法消毒处理医院污水,通过选用不同阳极材料构建的电化学体系,探讨电化学法的消毒机理。试验表明,以涂有贵金属(钌、铂和铱)氧化物的钛板作阳极,不锈钢板作阴极,在电流密度为8mA/cm^2、水力停留时间为15min、空气流量为40L/h、极水比为1.0的试验条件下,消毒后污水中总大肠菌群数(500cfu/L,达到国家一级排放标准(GB8978-1996)。  相似文献   
869.
近代以来,海洋灾害对沿海区域的社会经济发展造成了严重威胁。为应对发生的灾害,社会力量发挥了重要作用,成为救灾的主体。通过考察社会动员的主体、途径、力量等方面,探讨近代我国应对海洋灾害的社会动员机制,为我国未来应对突发性的海洋灾害提供历史借鉴,丰富应对措施与经验,保障人民生命财产安全。  相似文献   
870.
采用Fenton法对垃圾渗滤液膜滤浓缩液进行预处理,探讨了pH值、FeSO4/H2O2用量及比例、以及反应时间对CODcr及色度去除率的影响.研究结果表明:当pH =4.0,FeSO4/H2O2用量0.75/7.5 (g/ml),反应时间2.5h,垃圾渗滤液膜滤浓缩液的CODcr浓度从4 416 mg/L降低至630.7 ml/L,CODcr去除率达85.7%;色度从1 250倍降低至200倍以下,色度去除率达84%.因此,本工艺对垃圾渗滤液膜滤浓缩液的CODcr及色度具有较好的去除效果,作为垃圾渗滤液膜滤浓缩液的预处理工艺具有可行性.  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