全文获取类型
收费全文 | 1043篇 |
免费 | 114篇 |
国内免费 | 253篇 |
专业分类
安全科学 | 103篇 |
废物处理 | 52篇 |
环保管理 | 212篇 |
综合类 | 696篇 |
基础理论 | 105篇 |
污染及防治 | 136篇 |
评价与监测 | 47篇 |
社会与环境 | 44篇 |
灾害及防治 | 15篇 |
出版年
2024年 | 2篇 |
2023年 | 7篇 |
2022年 | 22篇 |
2021年 | 38篇 |
2020年 | 31篇 |
2019年 | 31篇 |
2018年 | 19篇 |
2017年 | 36篇 |
2016年 | 47篇 |
2015年 | 47篇 |
2014年 | 53篇 |
2013年 | 66篇 |
2012年 | 91篇 |
2011年 | 72篇 |
2010年 | 76篇 |
2009年 | 66篇 |
2008年 | 46篇 |
2007年 | 84篇 |
2006年 | 78篇 |
2005年 | 51篇 |
2004年 | 61篇 |
2003年 | 46篇 |
2002年 | 50篇 |
2001年 | 45篇 |
2000年 | 50篇 |
1999年 | 43篇 |
1998年 | 28篇 |
1997年 | 28篇 |
1996年 | 23篇 |
1995年 | 15篇 |
1994年 | 8篇 |
1993年 | 10篇 |
1992年 | 6篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 1篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1970年 | 1篇 |
排序方式: 共有1410条查询结果,搜索用时 320 毫秒
341.
探讨了加入WTO对贸易与环境管理职能的影响,强调突破绿色壁垒,必须发挥政府宏观调控职能,规范和发展环境产业市场,发展生态产业和绿色贸易。 相似文献
342.
为强化DBD(介质阻挡放电)技术对VOCs(挥发性有机物)的处理效果,采用溶胶凝胶法制备Bi2WO6/NH(NH为天然赤铁矿)复合催化剂,并利用DBD协同催化剂降解EA(ethyl acetate,乙酸乙酯).采用XRD(X射线衍射)仪、BET(比表面积及孔径)分析仪、SEM(扫描电子显微镜)分析仪对催化剂进行表征,对比分析DBD、DBD/Bi2WO6(DBD协同Bi2WO6)、DBD/NH(DBD协同NH)及DBD/Bi2WO6/NH(DBD协同Bi2WO6/NH复合催化剂)4个体系中EA去除率和能量产率随输入功率、初始ρ(EA)及气体停留时间的变化情况,同时探究输入功率和催化剂对ρ(O3)及矿化率的影响,并对降解产物进行分析.结果表明:①在不同工艺参数条件下,EA去除率和能量产率均表现为DBD/Bi2WO6/NH体系> DBD/NH体系> DBD/Bi2WO6体系> DBD体系.②EA去除率随输入功率的升高和气体停留时间的延长而增加,随初始ρ(EA)的升高而降低;但能量产率随输入功率的升高和气体停留时间的延长而降低,随初始ρ(EA)的升高而增加.③在输入功率为84 W、初始ρ(EA)为0.40 mg/L、气体流量为1.0 m3/h的条件下,相较于DBD体系,DBD/Bi2WO6/NH体系中EA去除率和矿化率分别提高了19.16%和14.44%,而ρ(O3)降低了74.47%.④DBD降解EA的最终产物主要为CO2、H2O及微量的CH4、CH3CH2OH及CH3COOH等小分子有机化合物.研究显示,DBD协同Bi2WO6/NH复合催化剂能够高效去除EA. 相似文献
343.
“十三五”期间,我国排污许可管理制度已基本建立;“十四五”时期,我国排污许可管理将逐步过渡到注重水质达标的管理阶段.为适应我国排污许可新的管理需求,研究了基于技术和水质相结合的排污许可限值核定技术.其中,基于技术的排放限值核定主要根据企业的行业属性和核定产能,结合环境影响评价批复的污染物排放额度,确定其排放浓度限值和排放总量限值;基于水质的排放限值核定需建立污染源与水质之间的响应关系,以地表水水质达标为目标,计算各污染源的最大允许排放量.最终的排污许可限值为基于技术的排污许可限值和基于水质的排污许可限值的最小值.以常州为例,从常州排污许可证核发重点行业选取了两家化工企业A和B,核算其基于技术的排放限值;采用水质模拟和污染物最大允许排放量分配技术,计算了污染物最大允许排放量,并分配到两家化工企业,作为基于水质的排放限值.结果表明:A化工企业CODCr和NH3-N的最终排污许可限值分别为6.53和0.075 t/a,其中,CODCr的最终取值为基于水质的排放限值,NH3-N基于技术和基于水质的排放取值相同;B化工企业CODCr和NH3-N的最终排放限值分别为11.60和0.17 t/a,最终取值均为基于技术的排放限值.研究显示,基于水质的排许可限值受到企业自身和外部水环境容量的双重影响,应从严制定排污许可限值,既能达到企业行业排放标准和环境影响评价批复的要求,又能满足水环境质量达标的目标. 相似文献
344.
345.
通过对影响我国经济-人口协调的主要因素进行分析,找出在人口系统福利与经济系统福利方面的冲突环节和发展障碍,从市场体制、人口管理体制、财税体制、领导干部政绩评价制度等方面寻找成因,提出切实可行的对策建议,为我国主体功能区经济-人口协调发展提供参考。 相似文献
346.
347.
虞静 《中国环境管理干部学院学报》2000,(2)
本文主要讨论了几种新型脱硫技术的脱硫原理和工艺,并对各项技术的综合性能进行了评价。同时,还指出烟气脱硫工艺的国产化是经济、有效减轻SO_2污染的必然趋势。 相似文献
348.
Permeable reactive barriers (PRBs) are an alternative technology to treat mine drainage containing sulfate and heavy metals. Two column experiments were conducted to assess the suitability of an organic carbon (OC) based reactive mixture and an Fe0-bearing organic carbon (FeOC) based reactive mixture, under controlled groundwater flow conditions. The organic carbon mixture contains about 30% (volume) organic carbon (composted leaf mulch) and 70% (volume) sand and gravel. The Fe0-bearing organic carbon mixture contains 10% (volume) zero-valent iron, 20% (volume) organic carbon, 10% (volume) limestone, and 60% (volume) sand and gravel. Simulated groundwater containing 380 ppm sulfate, 5 ppm As, and 0.5 ppm Sb was passed through the columns at flow rates of 64 (the OC column) and 62 (the FeOC column) ml d− 1, which are equivalent to 0.79 (the OC column) and 0.78 (the FeOC column) pore volumes (PVs) per week or 0.046 m d− 1 for both columns. The OC column showed an initial sulfate reduction rate of 0.4 µmol g (OC)− 1 d− 1 and exhausted its capacity to promote sulfate reduction after 30 PVs, or 9 months of flow. The FeOC column sustained a relatively constant sulfate reduction rate of 0.9 µmol g (OC)− 1 d− 1 for at least 65 PVs (17 months). In the FeOC column, the δ34S values increase with the decreasing sulfate concentration. The δ34S fractionation follows a Rayleigh fractionation model with an enrichment factor of 21.6‰. The performance decline of the OC column was caused by the depletion of substrate or electron donor. The cathodic production of H2 by anaerobic corrosion of Fe probably sustained a higher level of SRB activity in the FeOC column. These results suggest that zero-valent iron can be used to provide an electron donor in sulfate reducing PRBs. A sharp increase in the δ13C value of the dissolved inorganic carbon and a decrease in the concentration of HCO3− indicate that hydrogenotrophic methanogenesis is occurring in the first 15 cm of the FeOC column. 相似文献
349.
E. Safari M. Jalili Ghazizade M.A. Abduli B. Gatmiri 《Waste management (New York, N.Y.)》2014,34(8):1408-1415
Performance of compacted clay liners commonly used as landfill barrier systems can be subject to decline in terms of hydraulic conductivity if left exposed to atmospheric conditions for an extended period of time prior to placement of overlaying layers. The resulting desiccation cracking can lead to increased hydraulic conductivity. Desiccation crack intensity was studied for three clayey soils commonly used for construction of landfill barrier system in a relatively large scale test setup exposed to real time atmospheric conditions over a complete annual cycle. A white separator geotextile cover was presumed to be capable of reducing the intensity of desiccation cracking through absorbing and maintaining higher amounts of moisture and reducing the temperature of the soil surface in comparison to a directly exposed soil surface. Desiccation cracking was monitored using a digital imaging technique for three compacted clay liners in two sets, one open to air and the second covered with the white geotextile. Crack intensity factor approached a relatively stable phase after certain cycles corresponding to atmospheric dry wet cycles. The results indicated that the white separator geotextile was capable of reducing the crack intensity factor by 37.4–45.9% throughout the experiment including the cyclic phase of desiccation cracking. During the stable phase, the maximum reduction in crack intensity factor of 90.4% as a result of applying geotextile cover was observed for the soil with the lowest plastic index and clay content and therefore the lowest magnitude of crack intensity factor. The other two soils with similar clay content but different plastic index showed 23.6% and 52.2% reductions in crack intensity factor after cyclic phase when covered with geotextile. 相似文献
350.
Paul D. Bakke Robert Thomas Charles Parrett 《Journal of the American Water Resources Association》1999,35(4):911-921
ABSTRACT: A regional adjustment relationship was developed to estimate long-term (30-year) monthly median discharges from short term (three-year) records. This method differs from traditional approaches in that it is based on site-specific discharge data but does not require correlation of these data with discharges from a single hydrologically similar long-term gage. The method is shown to be statistically robust, and applicable to statistics other than the median. 相似文献