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   497篇
  免费   42篇
  国内免费   121篇
安全科学   72篇
废物处理   7篇
环保管理   139篇
综合类   205篇
基础理论   120篇
污染及防治   65篇
评价与监测   17篇
社会与环境   29篇
灾害及防治   6篇
  2024年   4篇
  2023年   10篇
  2022年   14篇
  2021年   20篇
  2020年   21篇
  2019年   20篇
  2018年   17篇
  2017年   15篇
  2016年   33篇
  2015年   31篇
  2014年   20篇
  2013年   27篇
  2012年   28篇
  2011年   38篇
  2010年   27篇
  2009年   48篇
  2008年   32篇
  2007年   54篇
  2006年   33篇
  2005年   19篇
  2004年   10篇
  2003年   23篇
  2002年   15篇
  2001年   21篇
  2000年   12篇
  1999年   4篇
  1998年   8篇
  1997年   16篇
  1996年   5篇
  1995年   6篇
  1994年   4篇
  1992年   2篇
  1990年   2篇
  1989年   2篇
  1988年   2篇
  1987年   2篇
  1986年   2篇
  1985年   2篇
  1984年   1篇
  1981年   1篇
  1980年   1篇
  1979年   2篇
  1978年   1篇
  1974年   1篇
  1973年   1篇
  1971年   3篇
排序方式: 共有660条查询结果,搜索用时 15 毫秒
651.
环境微界面过程是污染物在各环境要素中迁移转化的基本过程,也是研究污染控制方法的基础.发展原位和在线研究方法,对于揭示污染物在环境微界面的迁移转化规律和进行污染控制过程的研究具有重要意义.本文基于环境微界面过程的基本特征,在针对多相环境催化的原位研究方法基础上,分析了用于环境微界面过程的原位和在线研究方法所面临的挑战和相应对策,主要介绍了红外光谱、拉曼光谱和质谱等技术在气固环境微界面过程原位研究中的应用,提出了发展环境微界面过程原位和在线研究方法体系的构想.  相似文献   
652.
MC-LR removal performances under different AOPs were compared systematically. Higher removal efficiency and synergistic effects were obtained by combined process. The acute biotoxicity raised in different degrees after oxidation. Microcystin-LR attracts attention due to its high toxicity, high concentration and high frequency. The removal characteristics of UV/H2O2 and O3/H2O2 advanced oxidation processes and their individual process for MC-LR were investigated and compared in this study. Both the removal efficiencies and rates of MC-LR as well as the biotoxicity of degradation products was analyzed. Results showed that the UV/H2O2 process and O3/H2O2 were effective methods to remove MC-LR from water, and they two performed better than UV-, O3-, H2O2-alone processes under the same conditions. The effects of UV intensity, H2O2 concentration and O3 concentration on the removal performance were explored. The synergistic effects between UV and H2O2, O3 and H2O2 were observed. UV dosage of 1800 mJ·cm2 was required to remove 90% of 100 mg·L1 MC-LR, which amount significantly decreased to 500 mJ·cm2 when 1.7 mg·L1 H2O2 was added. 0.25 mg·L1 O3, or 0.125 mg·L1 O3 with 1.7 mg·L1 H2O2 was needed to reach 90% removal efficiency. Furthermore, the biotoxicity results about these UV/H2O2, O3/H2O2 and O3-alone processes all present rising trends with oxidation degree of MC-LR. Biotoxicity of solution, equivalent to 0.01 mg·L1 Zn2+, raised to 0.05 mg·L1 Zn2+ after UV/H2O2 or O3/H2O2 reaction. This phenomenon may be attributed to the aldehydes and ketones with small molecular weight generated during reaction. Advice about the selection of MC-LR removal methods in real cases was provided.  相似文献   
653.
铁屑法处理活性染料废水的实验研究   总被引:5,自引:0,他引:5  
研究了反应时间、染料浓度、进水pH以及不同的废铸铁屑投加量的条件下,废铸铁屑内电解法处理模拟印染废水的脱色能力。并采用铁屑滤床强化厌氧一好氧膜生物反应器(A/OMBR)处理含活性染料的模拟废水。研究结果表明,铁屑对模拟印染废水的最佳脱色时间为12min,酸性条件下铁屑的脱色率优于碱性条件.随铁屑投加量的增加,系统对印染废水的脱色率提高,铁屑滤床强化A/OMBR处理可以提高组合工艺出水色度和COD的去除率。  相似文献   
654.
转炉钢渣资源化处理及热闷生产工艺应用实例研究   总被引:1,自引:0,他引:1       下载免费PDF全文
主要对不同钢渣处理工艺进行对比,结合五矿营口年处理90万t转炉钢渣热闷以及钢渣破碎-筛分-磁选处理项目,分析热闷技术处理钢渣的优势,并通过两年多的生产线运行实践,各项生产指标趋于稳定,均达到设计要求,为企业取得良好的社会效益和经济效益。  相似文献   
655.
The wastewater effluent from Radix aconiti processing, an important step in the production processes of traditional Chinese medicine (TCM), is a type of toxic wastewater and difficult to treat. Plasma oxidation methods have emerged as feasible techniques for effective decomposition of toxic organic pollutants. This study examined the performance of a plasma reactor operated in a dielectric barrier discharge (DBD) to degrade the effluent from R. aconiti processing. The effects of treatment time, discharge voltage, initial pH value and the feeding gas for the reactor on the degradation of this TCM wastewater were investigated. A bacterium bioluminescence assay was adopted in this study to test the toxicity of the TCM wastewater after non-thermal plasma treatment. The degradation ratio of the main toxic component was 87.77% after 60 min treatment with oxygen used as feed gas and it was 99.59% when the initial pH value was 8.0. High discharge voltage and alkaline solution environment were beneficial for improving the degradation ratio. The treatment process was found to be capable of reducing the toxicity of the wastewater to a low level or even render it non-toxic. These experimental results suggested that the DBD plasma method may be a competitive technology for primary decomposition of biologically undegradable toxic organic pollutants in TCM wastewater.  相似文献   
656.
本文针对当前环境监测四级站的污染源监测特点,提出了双程序双样品的监测采样方法.可避免排污企业受自身利益的驱使而对污染物排放采取弄虚作假的行为,使污染源监测更为客观公正,有利于污染源的监督管理。  相似文献   
657.
Identification of the leakage of hazardous gases plays an important role in the environment protection, human health and safety of industry production. However, lots of current optimization algorithms, such as particle swarm optimization (PSO) and Grey Wolf Optimizer (GWO), suffer from poor global optimization capability and estimation accuracy. In this work, a hybrid differential evolutionary and GWO (DE-GWO) algorithm is proposed. Tested by simulation cases and Prairie Grass emission experimental data, DE-GWO shows higher estimation accuracy than GWO. Compared with the other four optimization algorithms, DE-GWO exhibits finer robust stability under different population sizes, fewer iterations, as well as higher estimation accuracy with fewer search agents. Importantly, simulation results demonstrate that DE-GWO is more suitable to apply in the scene with a small number of sensors. Therefore, the proposed in this paper outperforms other optimization algorithms for the gas emission inverse problem. DE-GWO can provide reliable estimation towards gas emission identification and positioning, which shows huge potential as the data analysis module of real-time monitoring and early warning system.  相似文献   
658.
为了更有效地评估和防范铁路数字移动通信系统(GSM-R)的安全风险,针对未考虑系统不同时期系统风险状况不同、研究多局限于静态评估的不足,提出基于马尔可夫链的风险指数量化计算方法,构建基于集对分析-吸收马尔可夫链的铁路数字移动通信系统(GSM-R)风险评估模型。首先使用吸收马尔可夫链对通信系统风险进行定量计算,运用集对分析关联度的同一性、差异性和矛盾性动态分析通信系统安全风险的趋势,通过结合马尔可夫链计算下一阶段的关联度以获得通信系统最终安全风险评估结果,选取通信系统6个时间段数据进行分析,并进行验证。结果表明:本文评估方法能实现铁路数字移动通信系统(GSM-R)安全风险的全面动态评估,验证通信系统安全风险动态评估模型的科学性、有效性和可行性。  相似文献   
659.
提出一种用于板料成形数值模拟的网格结点编号优化算法。该算法用各个结点的相邻单元结点编号总和除以该结点相邻单元数 ,所得的结点商作为重新结点编号的依据 ,对板料成形模拟的四边形单元结点编号进行优化 ,减少了带宽 ,减少有限元的计算贮存量 ,缩短了板料成形数值模拟的计算时间  相似文献   
660.
Coastal zones, which connect terrestrial and aquatic ecosystems, are among the most resource-rich regions globally and home to nearly 40% of the global human population. Because human land-based activities can alter natural processes in ways that affect adjacent aquatic ecosystems, land-sea interactions are increasingly recognized as critical to coastal conservation planning and governance. However, the complex socioeconomic dynamics inherent in coastal and marine socioecological systems (SESs) have received little consideration. Drawing on knowledge generalized from long-term studies in Caribbean Nicaragua, we devised a conceptual framework that clarifies the multiple ways socioeconomically driven behavior can link the land and sea. In addition to other ecosystem effects, the framework illustrates how feedbacks resulting from changes to aquatic resources can influence terrestrial resource management decisions and land uses. We assessed the framework by applying it to empirical studies from a variety of coastal SESs. The results suggest its broad applicability and highlighted the paucity of research that explicitly investigates the effects of human behavior on coastal SES dynamics. We encourage researchers and policy makers to consider direct, indirect, and bidirectional cross-ecosystem links that move beyond traditionally recognized land-to-sea processes.  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