全文获取类型
收费全文 | 815篇 |
免费 | 181篇 |
国内免费 | 526篇 |
专业分类
安全科学 | 90篇 |
废物处理 | 80篇 |
环保管理 | 68篇 |
综合类 | 809篇 |
基础理论 | 122篇 |
污染及防治 | 220篇 |
评价与监测 | 68篇 |
社会与环境 | 26篇 |
灾害及防治 | 39篇 |
出版年
2024年 | 8篇 |
2023年 | 37篇 |
2022年 | 53篇 |
2021年 | 56篇 |
2020年 | 69篇 |
2019年 | 47篇 |
2018年 | 59篇 |
2017年 | 82篇 |
2016年 | 97篇 |
2015年 | 72篇 |
2014年 | 75篇 |
2013年 | 107篇 |
2012年 | 106篇 |
2011年 | 98篇 |
2010年 | 60篇 |
2009年 | 72篇 |
2008年 | 48篇 |
2007年 | 82篇 |
2006年 | 54篇 |
2005年 | 40篇 |
2004年 | 41篇 |
2003年 | 30篇 |
2002年 | 25篇 |
2001年 | 21篇 |
2000年 | 16篇 |
1999年 | 11篇 |
1998年 | 8篇 |
1997年 | 8篇 |
1996年 | 7篇 |
1995年 | 8篇 |
1994年 | 10篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1987年 | 1篇 |
1980年 | 2篇 |
1975年 | 1篇 |
排序方式: 共有1522条查询结果,搜索用时 18 毫秒
71.
The purpose of this work was to study the distribution of airborne particles in the surroundings of an iron and steel factory in southern Finland. Several sources of particulate emissions are lying side by side, causing heavy dust loading to the environment. This complicated multi-pollutant situation was studied mainly by SEM/EDX methodology.Particles accumulated on Scots pine bark were identified andquantitatively measured according to their element content,size and shape. As a result, distribution maps of particulateelements were drawn and the amount of different particle typesalong the study lines was plotted. Particulate emissions fromthe industrial or energy production processes were not themain dust source. Most emissions were produced from theclinker crusher. Numerous stockpiles of the industrial wastesand raw materials also gave rise to particulate emissions as aresult of wind erosion. It was concluded that SEM/EDXmethodology is a useful tool for studying the distribution ofparticulate pollutants. 相似文献
72.
分别于2012年9月对不同盐度水体的查干湖和新立城水进行水体野外采样和室内实验分析,通过测定颗粒物、CDOM等光学活性物质的吸收系数来对比分析两种水体的光学活性物质的吸收特性、来源及其在400~700 nm范围内对总吸收系数的贡献.结果表明,综合营养状态评价指数显示秋季查干湖、新立城水库水体属于中等富营养化,总悬浮颗粒物的吸收光谱表现均与色素类颗粒物吸收光谱相似.对于盐度较大的查干湖水体(EC=988.87μS·cm~(-1)),非藻类颗粒物占主导地位,各组分贡献率为非藻类颗粒物色素颗粒物CDOM;而盐度较低的新立城水库水体(EC=311.67μS·cm~(-1)),色素颗粒物贡献率略大于非藻类颗粒物贡献,各组分贡献率依次为:色素颗粒物非藻类颗粒物CDOM.查干湖总悬浮颗粒物吸收系数α_p(440)、α_p(675)和非藻类颗粒物吸收系数α_d(440)分别与TSM(总悬浮颗粒物)、ISM(无机悬浮颗粒物)和OSM(有机悬浮颗粒物)、Chl-a(叶绿素a)相关性均较好,相关系数在0.55以上;新立城水库α_p(440)、α_p(675)与Chl-a相关性较好(0.77和0.85,P0.05),α_d(440)与ISM具有相关性(0.74,P0.01),与OSM表现为负相关(-0.63,P0.05).查干湖CDOM吸收系数a_g(440)仅与OSM表现为负相关性(-0.54,P0.05),而新立城水库α_g(440)与其他参数均无相关性.通过对CDOM吸收曲线在250~400 nm的拟合所得到的S_g以及相对分子量M_r发现,查干湖的S_g[(0.021±0.001)m~(-1)]大于新立城的S_g[(0.017 6±0.001)m~(-1)],而CDOM的相对分子量M_r值分别为11.44±2.00(7.5~15.09)、7.53±0.79(6.17~8.89),查干湖M_r值高于新立城水库水体,表明查干湖CDOM组成较新立城水体中CDOM的分子量小,组成更趋向于小分子.查干湖受风速和湖岸坍塌的影响产生矿物悬浮、沉积微粒,水体颗粒物以非藻类为主,部分来自于浮游植物降解产物;新立城水库水体不仅有径流携带的陆源性无机物的输入,同时水体浮游植物生长减弱且微生物分解活动加强,降解有机颗粒物与非藻类吸收系数呈现负相关. 相似文献
73.
为了解西安市气象条件对霾污染天气的影响,利用西安市13个测点PM2.5逐时监测资料和气温(T)、风向(WD)、风速(WS)、相对湿度(RH)、气压(p)以及能见度(VIS)等地面气象观测数据,对西安市2013年12月16—26日发生的一次严重霾污染过程进行分析。结果表明:此次霾污染过程中,西安市PM2.5日均值浓度最高达744μg/m3,超过国家二级标准近10倍,能见度最低降至0.42 km,重霾污染期间PM2.5/PM10在64%~80%。分析认为高相对湿度、低风速和主导风向不明显以及大气层结稳定是造成本次霾污染天气的主要气象因素,其中大气能见度与风速和大气压呈正相关,其相关系数(r)分别为0.3162、0.3479,能见度与温度的相关系数r=0.0825,呈微弱正相关,能见度和相对湿度的相关系数r=-0.7465,呈显著负相关。细颗粒物对能见度的影响非常明显,二者之间的相关系数为-0.7290,细颗粒污的消光系数最高达9.2 km-1。 相似文献
74.
以湖南长沙某铬盐厂铬渣为研究对象,通过室内模拟实验,采用振荡淋洗方法研究了硫酸-硫酸钠复合淋洗剂对铬渣污染场地Cr的淋洗效果,探讨了淋洗剂浓度、液固比和淋洗时间等对淋洗效果的影响,以及淋洗前后重金属形态的变化,并通过对比试验研究了硫酸钠、柠檬酸、草酸、Na2-EDTA、硫酸、柠檬酸-柠檬酸三钠以及盐酸-氯化钠作为淋洗剂对总铬和六价铬的淋洗效果。结果表明:硫酸/硫酸钠复合淋洗剂在浓度为0.4 mol/L,液固比为20∶1,反应时间为6 h,常温条件下可以达到最佳淋洗效果,总铬和六价铬的浸出效率分别为70.35%和71.56%;另外,重金属形态分析表明,该复合淋洗剂有效减少了铬渣中弱酸可提取态和有机物结合态Cr的百分比,使得残渣态Cr的百分比增加,从而降低了Cr的活性,达到修复目的。淋洗剂对比试验结果表明,与其他淋洗剂相比,硫酸-硫酸钠淋洗效果最好,其中的氢离子能与Cr~(3+)进行离子交换,而硫酸根能够有效地将钙与六价铬分离,对此高钙铬渣的处理更具针对性和有效性。 相似文献
75.
为探究热工艺过程产生的热气流作用下颗粒的迁移规律,基于气固两相离散粒子模型(DPM)对多源浮射流伴生的高温颗粒的扩散特性进行了数值研究,讨论了两相流运动过程中热气流与颗粒群的温度和速度的瞬时变化情况.结果表明,对于473K£T0£673K的高温颗粒群,温度衰减趋势类似,颗粒群温度分布呈中心对称;当5μm£dp£20μm时,颗粒与气流之间的跟随性随着粒径的增大而降低;热羽流随时间经历了独立发展和相互合并的过程,羽流之间涡旋结构的消失导致中心位污染源散发的dp=10μm的颗粒更容易发生沉降. 相似文献
76.
77.
太湖湖滨带林草复合带草本植物枯落物量的变化特征 总被引:1,自引:1,他引:1
为减少湖滨带林带枯落物的产生,有效降低N、P随降水径流进入湖泊水体的风险,采用人工草坪替代林下杂草的方式,建立林草复合带.以5种草坪草为研究对象,设立3种种植密度,采用定位定期采集的方法,研究草坪建植后草本植物枯落物的变化以及不同种植密度对枯落物量的影响.结果表明:①间距15 cm高密度种植易导致草坪枯落物的产生,以白三叶和红花酢浆草较突出;草坪种植后林下草本植物枯落物量大幅度减少,平均枯落物量减少66%~95%.②草坪枯落物量随生长时间变化无明显规律,7—11月植物生长期间,白三叶草坪10月枯落物量最高;麦冬草坪、红花酢浆草草坪以及与其混种的其他草坪枯落物量最高时期均出现于8月.③白三叶高、低密度种植单种草坪产生的枯落物量大于与红花酢浆草混种草坪,而中密度种植则相反,单种草坪小于混种草坪. 相似文献
78.
Jinzhuo Zhao Cuiqing Liu Yuntao Bai Tse-yao Wang Haidong Kan Qinghua Sun 《环境科学学报(英文版)》2015,27(5):98-103
Epidemiological studies have found that individuals with diabetes mellitus(DM) display an increased susceptibility for adverse cardiovascular outcomes when exposed to air pollution.This study was conducted to explore the potential mechanism linking ambient fine particles(PM2.5) and heart injury in a Type 2 DM(T2DM) animal model. The KKay mouse, an animal model of T2DM, was exposed to concentrated ambient PM2.5 or filtered air for 8 weeks via a versatile aerosol exposure and concentrator system. Simultaneously, an inhibitor of IκB kinase-2(IKK-a)(IMD-0354), which is a blocker of nuclear factor κB(NF-κB)nuclear translocation, was administrated by intracerebroventricular injection(ICV) to regulate the NF-êB pathway. The results showed that ambient PM2.5 induced the increase of, NF-êB, cyclooxygenase-2(COX-2) and mitogen activated protein kinase(MAPK) expression in cardiac tissue, and that IMD-0354 could alleviate the inflammatory injury. The results suggested that the NF-êB pathway plays an important role in mediating the PM2.5-induced cardiovascular injury in the T2DM model. Inhibiting NFκB may be a therapeutic option in air-pollution-exacerbated cardiovascular injury in diabetes mellitus. 相似文献
79.
Nimisha Singh 《Environmental pollution (Barking, Essex : 1987)》2009,157(2):371-376
Leaching of Cu and Zn from a composite of spent antifouling paint particles, containing about 300 mg g−1 and 110 mg g−1 of the respective metals, was studied in batch experiments. For a given set of simulated environmental conditions, release of Cu was independent of paint particle concentration due to attainment of pseudo-saturation, but Zn was less constrained by solubility effects and release increased with increasing particle concentration. Leaching of Cu increased but Zn decreased with increasing salinity, consistent with mechanisms governing the dissolution of Cu2O in the presence of chloride and Zn acrylates in the presence of seawater cations. Because of complex reaction kinetics and the presence of calcium carbonate in the paint matrix, metal leaching appeared to be greater at 4 °C than 19 °C under many conditions. These findings have important environmental and biological implications regarding the deliberate or inadvertent disposal of antifouling paint residues. 相似文献
80.
Wei Jiang 《Environmental pollution (Barking, Essex : 1987)》2009,157(5):1619-1625
Toxicity of nano-scaled aluminum, silicon, titanium and zinc oxides to bacteria (Bacillus subtilis, Escherichia coli and Pseudomonas fluorescens) was examined and compared to that of their respective bulk (micro-scaled) counterparts. All nanoparticles but titanium oxide showed higher toxicity (at 20 mg/L) than their bulk counterparts. Toxicity of released metal ions was differentiated from that of the oxide particles. ZnO was the most toxic among the three nanoparticles, causing 100% mortality to the three tested bacteria. Al2O3 nanoparticles had a mortality rate of 57% to B. subtilis, 36% to E. coli, and 70% to P. fuorescens. SiO2 nanoparticles killed 40% of B. subtilis, 58% of E. coli, and 70% of P. fluorescens. TEM images showed attachment of nanoparticles to the bacteria, suggesting that the toxicity was affected by bacterial attachment. Bacterial responses to nanoparticles were different from their bulk counterparts; hence nanoparticle toxicity mechanisms need to be studied thoroughly. 相似文献