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   2148篇
  免费   204篇
  国内免费   744篇
安全科学   256篇
废物处理   103篇
环保管理   195篇
综合类   1404篇
基础理论   356篇
环境理论   1篇
污染及防治   454篇
评价与监测   107篇
社会与环境   96篇
灾害及防治   124篇
  2024年   13篇
  2023年   48篇
  2022年   124篇
  2021年   117篇
  2020年   100篇
  2019年   86篇
  2018年   97篇
  2017年   105篇
  2016年   115篇
  2015年   168篇
  2014年   158篇
  2013年   226篇
  2012年   198篇
  2011年   212篇
  2010年   170篇
  2009年   136篇
  2008年   143篇
  2007年   139篇
  2006年   125篇
  2005年   94篇
  2004年   66篇
  2003年   54篇
  2002年   63篇
  2001年   70篇
  2000年   42篇
  1999年   43篇
  1998年   32篇
  1997年   27篇
  1996年   25篇
  1995年   27篇
  1994年   15篇
  1993年   13篇
  1992年   9篇
  1991年   10篇
  1990年   10篇
  1989年   4篇
  1988年   7篇
  1987年   1篇
  1986年   3篇
  1985年   1篇
排序方式: 共有3096条查询结果,搜索用时 908 毫秒
521.
利用助剂法降低催化裂化再生烟气SOx排放   总被引:4,自引:0,他引:4  
由于加工原油重质比,SOx排放问题日益严重,为满足环保法规要求,我们应用了硫转移助剂,并进行了相关的技术及经济分析。  相似文献   
522.
Air sparging (AS) is one of the groundwater remediation techniques for remediating volatile organic compounds (VOCs) in saturated soil. However, in spite of the success of air sparging as a remediation technique for the cleanup of contaminated soils, to date, the fundamental mechanisms or the physics of air flow through porous media is not well understood. In this study, centrifugal modeling tests were performed to investigate air flow rates and the evolution of the zone of influence during the air sparging under various g-levels. The test results show that with the increase in sparging pressure the mass flow rate of the air sparging volume increases. The air mass flow rate increases linearly with the effective sparging pressure ratio, which is the difference between sparging pressure and hydrostatic pressure normalized with respect to the effective overburden pressure at the sparging point. Also the slope of mass flow rate with effective sparging pressure ratio increases with higher g-levels. This variation of the slope of mass flow rate of air sparging volume versus effective sparging pressure ratio, M, is linear with g-level confirming that the air flow through soil for a given effective sparging pressure ratio only depends on the g-level. The test results also show that with increasing sparging pressure, the zone of influence (ZOI), which consists of the width at the tip of the cone or lateral intrusion and the cone angle, will lead to an increase in both lateral intrusion and the cone angle. With a further increase in air injection pressure, the cone angle reaches a constant value while the lateral intrusion becomes the main contributor to the enlargement of the ZOI. However, beyond a certain value of effective sparging pressure ratio, there is no further enlargement of the ZOI.  相似文献   
523.
Journal of Material Cycles and Waste Management - Dephosphorization slag is primarily composed of CaO–SiO2–FeO–P2O5 slag system. As it contains abundant valuable components,...  相似文献   
524.
Previous assessments of the effectiveness of protected areas (PAs) focused primarily on changes in human pressure over time and did not consider the different human-pressure baselines of PAs, thereby potentially over- or underestimating PA effectiveness. We developed a framework that considers both human-pressure baseline and change in human pressure over time and assessed the effectiveness of 338 PAs in China from 2010 to 2020. The initial state of human pressure on PAs was taken as the baseline, and changes in human pressure index (HPI) were further analyzed under different baselines. We used the random forest models to identify the management measures that most improved effectiveness in resisting human pressure for the PAs with different baselines. Finally, the relationships between the changes in the HPI and the changes in natural ecosystems in PAs were analyzed with different baselines. Of PAs with low HPI baselines, medium HPI baselines, and high HPI baselines, 76.92% (n=150), 11.11% (n=12), and 22.86% (n=8) , respectively, showed positive effects in resisting human pressure. Overall, ignoring human-pressure baselines somewhat underestimated the positive effects of PAs, especially for those with low initial human pressure. For PAs with different initial human pressures, different management measures should be taken to improve effectiveness and reduce threats to natural ecosystems. We believe our framework is useful for assessing the effectiveness of PAs globally, and we recommend it be included in the Convention on Biological Diversity Post-2020 Strategy.  相似文献   
525.
Environmental Science and Pollution Research - The problems of data leakage and unreliable information transfer in the management process make sustainability management an inevitable need for...  相似文献   
526.
Environmental Science and Pollution Research - Prefabrication has been generating increasing interest as a cleaner production strategy to promote sustainable development. Alongside this trend,...  相似文献   
527.
Jiang  Dongmei  Jiang  Kunhong  Li  Rui  Zhao  Liangbin  Liu  Zile  Xiong  Bangjie  Jin  Du  Hao  Xiaoxia  Zhu  Li  Kang  Bo  Bai  Lin 《Environmental science and pollution research international》2022,29(36):54378-54390

The disposal of organic waste by the biocomposting of black soldier fly larvae (BSFL) has drawn broad attention. However, the discrepancies in heavy metal immobilization between BSFL biocomposting with different inoculation densities and aerobic composting need to be further researched. In this study, BSFL with inoculation densities of 0.08%, 0.24% and 0.40% was added to swine manure to investigate its influence on heavy metal bioaccumulation and bioavailability. The physicochemical properties, BSFL growth performance and amino acid contents were measured. The results showed that the germination index, total prepupal yield and bioavailable fraction removal rate (%) of Cr and Pb at an inoculation density of 0.40% of BSFL were the highest among all of the BSFL biocomposting groups. Although the bioaccumulation factor and heavy metal (Cd, Cr, Cu and Zn) concentrations of the BSFL body from swine manure with inoculation densities of 0.24% and 0.40% of BSFL were similar, the BSFL inoculation density of 0.40% had the best absorption effect on these heavy metals in terms of total prepupal yield. Therefore, this study provides a basis for exploring the optimal inoculation density of BSFL biocomposting to reduce the harmful effects of heavy metals in swine manure.

  相似文献   
528.
基于2017年濮阳市第二次全国污染源普查数据,采用聚类分析和核密度分析的方法对濮阳市行业结构特征、工业污染集聚特征进行了分析。结果表明,濮阳市支柱行业为石化行业,工业总产值占比36.92%,远高于其他行业;非金属矿物制品企业数量最多,污染物排放总量最高;颗粒物排放量占濮阳市工业污染源排放总量的33%,占比最高;非金属矿物制品业与石油、煤炭及其他燃料加工业是濮阳市废气污染物的主要来源,石油、煤炭及其他燃料加工业与农副产品加工业是濮阳市废水污染物的主要来源;濮阳市产业集聚区是污染物产排的重要区域,其污染物产生量占濮阳市污染物产生总量的95.49%,污染物排放量占濮阳市排放总量的63.05%。而非产业集聚区的污染物排放量占濮阳市排放总量的36.95%,是精准治污的重点。针对濮阳市产业结构和产业布局现状,提出,重新整合辖区非金属矿物制品业,继续做强石化行业,兼顾发展污染物排放强度低的行业;挖掘产业集聚区减排潜力,建设绿色产业集聚区是经济与环境协调发展的重要途径;非产业集聚区企业应因地制宜,政策引导,发挥中小企业自主能动性,提升环境质量。以期为濮阳市产业布局调整提供技术支持。  相似文献   
529.
为全面辨识系统风险并准确评估系统安全状况,从3元空间(信息-物理-社会)融合视角出发,界定安全态势感知概念并解读其内涵,提出安全态势感知概念模型和理论模型,并解析安全态势数据采集层、觉察层、理解层、投射层和预警层的具体内涵和功能。研究结果表明:3元空间融合视阈下的安全态势感知,能够通过物联网和互联网同步采集安全态势数据,在现有安全态势感知(安全态势信息输入、处理、输出)基础上,实现对人、机、物及其相互关系的整体感知,有效应对当前复杂多变的安全态势,为安全态势感知体系优化提供理论指导。  相似文献   
530.
基于知识的AVHRR影像的水体自动识别方法与模型研究   总被引:34,自引:4,他引:34  
根据水体光谱特性,通过分析水体在NOAA气象卫星的AVHRR影像上的表象特征及与其它相关环境因子在光谱信息上的差异,认为水体在AVHRR影像上具有光谱可分辨性,从而提出了基于水体光谱知识的水体自动提取识别的水体描述模型,并将该模型应用于太湖、淮河、渤海等地区,取得较好的效果。该模型方法同样可扩展应用于其它传感器获得的影像数据,从而实现遥感信息提取的自动化与智能化  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