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   941篇
  免费   41篇
  国内免费   383篇
安全科学   64篇
废物处理   50篇
环保管理   74篇
综合类   502篇
基础理论   187篇
污染及防治   350篇
评价与监测   36篇
社会与环境   35篇
灾害及防治   67篇
  2023年   28篇
  2022年   57篇
  2021年   40篇
  2020年   33篇
  2019年   28篇
  2018年   34篇
  2017年   49篇
  2016年   60篇
  2015年   71篇
  2014年   70篇
  2013年   100篇
  2012年   78篇
  2011年   108篇
  2010年   81篇
  2009年   50篇
  2008年   70篇
  2007年   55篇
  2006年   50篇
  2005年   49篇
  2004年   32篇
  2003年   26篇
  2002年   26篇
  2001年   21篇
  2000年   20篇
  1999年   28篇
  1998年   20篇
  1997年   15篇
  1996年   16篇
  1995年   23篇
  1994年   9篇
  1993年   5篇
  1992年   4篇
  1991年   2篇
  1990年   3篇
  1989年   1篇
  1988年   1篇
  1984年   1篇
  1982年   1篇
排序方式: 共有1365条查询结果,搜索用时 0 毫秒
81.
水泥窑协同处置过程中Pb、Cd的挥发特性   总被引:4,自引:0,他引:4  
对铅、镉2种重金属的氧化物开展了热重实验、熟料煅烧以及熟料消解实验,以重金属的挥发率为主要指标,研究了水泥窑协同处置过程中铅、镉在等温条件下随时间的挥发特性。结果表明,2种重金属的挥发率均是随温度的升高,时间的增加而增大。Pb的挥发率为96%,Cd的挥发率达到98%,根据等温动力学及阿累尼乌斯方程,对Pb,Cd的挥发率随时间变化的规律进行动力学模拟,得到较好的线性拟合效果,其中,Pb挥发反应的表观活化能E为88.73 kJ/mol,Cd挥发反应可以分2个部分:1 200℃以下的表观活化能E为61 kJ/mol;1 250℃以上的表观活化能E为184.6 kJ/mol。  相似文献   
82.
The aim of this study was to evaluate the toxicological responses of earthworm (Eisenia fetida) induced by field-contaminated, metal-polluted soils. Biochemical responses and DNA damage of earthworm exposed to two multi-metal-contaminated soils in a steel industry park and a natural reference soil in Zijin Mountain for 2, 7, 14, and 28 days were studied. Results showed that three enzyme activities, including superoxide dismutase (SOD), acetylcholinesterase (AChE), and cellulase, in earthworm in metal-contaminated soils were significantly different from those of the reference soil. Cellulase and AChE were more sensitive than SOD to soil contamination. The Olive tail moment of the comet assay after 2-day exposure increased 56.5 and 552.0 % in two contaminated soils, respectively, compared to the reference soil. Our findings show that cellulase and DNA damage levels can be used as potential biomarkers for exposure of earthworm to metal-polluted soils.  相似文献   
83.
添加氮损失抑制剂对蓝藻泥堆肥质量的影响   总被引:1,自引:0,他引:1  
对脱水蓝藻进行大型生产性堆肥实验。研究堆肥过程中,氮损失抑制剂过磷酸钙的添加对堆肥物料各类理化性质的影响。研究结果表明,过磷酸钙加入的处理组与未加过磷酸钙的对照组堆制37 d后堆肥物料均可腐熟,且堆肥肥效均符合NY525-2002的相关要求。添加过磷酸钙处理组有机质含量为490 g/kg,全N、全P和全K含量分别为20.75、10.02和11.32 g/kg,总养分含量达到9.77%,堆肥品质明显优于对照处理。同时,在微生物的作用下,对照组中微囊藻毒素MC-RR与微囊藻毒素MC-LR去除率分别达到89.8%与78.3%。值得一提的是,添加过磷酸钙后,MC-RR和MC-LR的去除率得到进一步提高,分别达到了92.96%和100%,较好地保证了蓝藻堆肥农用的安全性,为脱水蓝藻好氧堆肥化提供了可行性依据。  相似文献   
84.
The disturbance of highway construction upon surrounding vulnerable ecosystems is a common threat in the Longitudinal Range Gorge Region of southwestern China. We evaluated the disturbance of highway on plant species richness and diversity and soil nutrients from adjacent to the highway to 300 m upslope and 100 m downslope in forests and grasslands by setting 12 belt transects in forests and grasslands (six belt transects and six control belt transects, respectively). The results showed that there were some significant variances in belt transects with respective control belt transects for species richness and diversity in both forests and grasslands. Species richness and diversity of trees were lower within a 50-m distance from the highway and more noticeable on the downslope portion. Species richness and diversity of shrubs and herbs appeared higher near highway edge. Both species richness and diversity of herbs were similar in forests. In addition, exotic species, such as Eupatorium adenophorum, were further from the road and more widely dispersed in grasslands. Soil nutrients except total potassium (TK) were lower in the downslope area adjacent to highway edge and showed a significant increase with increasing distance from the highway in both forests and grasslands. This indicates that grasslands acted as microhabitats for exotic species and are more easily to be invaded than forests, especially if disturbed. Once destroyed, plant species and soil nutrients will require a significant amount of time to be restored to control levels. This work illustrates that the effects extend considerably to distances upslope and downslope from the construction site. Given that these changes occurred relatively quickly, the study suggests that the environmental "footprint" grows far beyond the road and adjacent zone of disruption.  相似文献   
85.
碘量法测定水中溶解氧有关问题的探讨及改进   总被引:4,自引:0,他引:4  
碘量法测定溶解氧时,采用NH3·H2O—KI代替NaOH(KOH)—KI固定溶解氧,用H2SO4—H3PO(41+1)混合酸代替H2SO4溶解沉淀,使沉淀沉降速度加快,分界线明显,沉淀溶解也更完全。同时做样品空白实验,校正了氧化还原性物质产生的干扰,对废水有明显的抗干扰能力。通过对蒸馏水、自来水、池塘水、废水进行溶解氧测定,结果均非常满意。  相似文献   
86.
Steroid estrogens such as estrone (E1), 17β-estradiol (E2), estriol (E3), and 17α-ethynylestradiol (EE2) have been suspected to be the main contaminants, which can affect the endocrine system of animals. Many authors have investigated these chemicals in the domestic wastewater treatment plants (WTP). However, wastewater from industries producing steroid contraceptives has not got ample attention. From the environmental point of view, the four steroids are very significant because even very low concentrations (ng/L) can cause reproductive disturbances in human, livestock and wildlife. The main purpose of the present investigation was to develop an analytical method for the determination of the four steroid estrogens present in WTP of a pharmacy factory, mainly producing contraceptive medicine in Beijing, China. Analysis was performed by solid-phase extraction (SPE) system and liquid chromatography combined with tandem mass spectrometry (LC/MS/MS). The average recoveries from effluent samples ranged from 88% to 103% and the precision of the method ranged from 9% to 4%. Based on 0.5-L wastewater samples, the limit of quantification (LOQ) was determined at 0.7 ng/L for E1, 0.8 for E2, 0.9 ng/L for E3, and 0.5 ng/L for EE2 in influent, and 1.0 ng/L for E2 and EE2, and 2.0 ng/L for E1 and E3 in effluent. In the influent samples, average concentrations of 80, 85, 73 and 155 ng/L were determined for E1, E2, E3 and EE2, respectively, showing that they were removed in this WTP to the extent of 79, 73, 85 and 67%, respectively.  相似文献   
87.
阐述了企业在实施节能降耗过程中普遍采用的节能量计算方法,对产品单耗节能量和技术措施节能量进行了分析,并对比了采用单耗法和技术措施法计算节能量的适用范围和局限性,指出两种方法对企业的意义,提出了在节能量计算过程中的注意事项和几点认识。  相似文献   
88.
埋地管道的腐蚀是影响油气田地面工程安全运行的重要因素之一,玻璃钢管道的非金属特性根除了腐蚀环境的形成,杜绝了管道腐蚀穿孔事件的发生,降低了污染土壤等环境问题发生的机率,塔里木油田管道服役现状、史密斯公司30a的研究结果对此做了充分的诠释。英—红外输油管道和哈森-威廉姆斯公式分别从实践和理论上展示了玻璃钢管卓越的水力特性,英买力潜山玻璃钢管线具有良好的经济和社会效益。  相似文献   
89.
有机污染物土地生物处理过程动态规律模拟研究   总被引:2,自引:0,他引:2  
刘凌  崔广柏  夏自强 《环境科学》2001,22(2):101-105
应用土壤颗粒内部有机污染物屏蔽理论,说明土地生物处理过程中残余有机污染物在土壤中的滞留现象,提出描述有机污染物在土壤及相连的水环境中生物降解过程的数学模型.其中,污染物的扩散过程用Fick第二扩散定律表示,可逆的吸附和解吸过程用线性吸附等温线表示,不可逆的土壤颗粒内部屏蔽过程用假一级反应动力学方程表示,生物降解过程用Monod动力学方程表示.模型计算结果与实验结果基本拟合,表示模型基本可靠.利用该数学模型,可以定量预测有机污染物进行土地生物处理所需的时间、处理的程度及动态规律.  相似文献   
90.
本文概括介绍了PPE信息管理系统。该系统是根据国标委和国家安监总局的信息化建设总要求,结合全国个体防护装备(PPE)标委会实际研发的,包括PPE标准化工作管理、标准全程控制、PPE辅助决策3个子系统。该系统打造了PPE标委会的信息化管理平台,满足了标准化工作对信息化管理的需要,提高了信息化管理水平。利用这个平台,标委会能够实现技术培训、信息发布、标准查询、辅助决策等功能,从而全面提升本领域标准化管理水平,促进本行业发展。  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