全文获取类型
收费全文 | 905篇 |
免费 | 57篇 |
国内免费 | 307篇 |
专业分类
安全科学 | 48篇 |
废物处理 | 69篇 |
环保管理 | 53篇 |
综合类 | 484篇 |
基础理论 | 190篇 |
污染及防治 | 325篇 |
评价与监测 | 51篇 |
社会与环境 | 28篇 |
灾害及防治 | 21篇 |
出版年
2023年 | 10篇 |
2022年 | 57篇 |
2021年 | 37篇 |
2020年 | 30篇 |
2019年 | 25篇 |
2018年 | 42篇 |
2017年 | 35篇 |
2016年 | 47篇 |
2015年 | 62篇 |
2014年 | 63篇 |
2013年 | 90篇 |
2012年 | 71篇 |
2011年 | 79篇 |
2010年 | 62篇 |
2009年 | 71篇 |
2008年 | 67篇 |
2007年 | 52篇 |
2006年 | 56篇 |
2005年 | 31篇 |
2004年 | 30篇 |
2003年 | 29篇 |
2002年 | 21篇 |
2001年 | 37篇 |
2000年 | 17篇 |
1999年 | 17篇 |
1998年 | 29篇 |
1997年 | 26篇 |
1996年 | 15篇 |
1995年 | 16篇 |
1994年 | 8篇 |
1993年 | 12篇 |
1992年 | 11篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 5篇 |
1983年 | 1篇 |
排序方式: 共有1269条查询结果,搜索用时 437 毫秒
991.
992.
993.
Lead in paddy soils and rice plants and its potential health risk around Lechang lead/zinc mine, Guangdong, China 总被引:15,自引:0,他引:15
As part of a project on phytoextraction of lead (Pb) in paddy soils around a lead/zinc (Pb/Zn) Mine in Lechang of Guangdong Province, South China, the concentration distribution of Pb in paddy soil-rice system was investigated, and its potential health risk to animal/human was evaluated. Total and diethylenetetraminepentaacetic acid (DTPA)-extractable Pb in soils averaged 1486 and 268 microg/g, respectively. According to sequential extraction procedure, soil Pb occurred primarily in the residual, carbonate and exchangeable fractions (30.2%, 26.7% and 19.1%, respectively). Lead extracted by the gastric juice simulation test (GJST) was 1068 microg/g and accounted for 75.4% of the total concentration. Mean Pb concentrations of 419 microg/g in rice root, 69.1 microg/g in whole straw, 51.0 microg/g in part straw (without two leaves near above the root), 44.9 microg/g in stalk, 21.9 microg/g in hull, 13.2 microg/g in grain with hull and 4.67microg/g in grain without hull (namely, unpolished rice) were found. Lead concentrations in both soil and rice plant were far above the corresponding tolerable levels. Lead daily intakes by local residents were 2.6 mg for adults and 1.2 mg for children, which were much higher than the allowable level. Thus, Pb in this area might pose a potential health risk to the local population. 相似文献
994.
在UASB反应器中接种好氧污泥培养厌氧颗粒污泥进行启动,研究不同浓度老龄(13年)垃圾渗滤液对处理效果的影响情况。通过保持进水COD浓度不变、逐步缩短HRT从而提高容积负荷到20 g COD/(L.d)的方法,可以培育出直径为1~3 mm颗粒污泥,最终产气量稳定在60~70 L/d,甲烷含量在50%~70%之间,COD去除率保持在90%左右,污泥层最底部MLSS为50 g/L。逐步提高进水中渗滤液的含量考察其对处理效果的影响,当进水为100%渗滤液时日产气量为500 mL/d、COD去除率仅为10%,表明渗滤液中多为难降解性有机物质。 相似文献
995.
996.
MnO2-loaded D301 weak basic anion exchange resin has been used as adsorbent to simultaneously remove lead and cadmium
ions from aqueous solution. The e ects of adsorbent dosage, solution pH and the coexistent ions on the adsorption were investigated.
Experimental results showed that with the adsorbent dosage more than 0.6 g/L, both Pb2+ and Cd2+ were simultaneously removed at
pH range 5–6. Except for HPO4
2??, the high concentration coexistent ions such as Na+, K+, Cl??, NO3??, SO4
2?? and HCO3??, showed no
significant e ect on the removal e ciency of both Pb2+ and Cd2+ under the experimental conditions. The coexistence of Mg2+, Ca2+
caused the reduction of Cd2+ removal, but not for Pb2+. The adsorption equilibrium for Pb2+ and Cd2+ could be excellently described
by the Langmuir isotherm model with R2 > 0.99. The maximum adsorption capacity was calculated as 80.64 mg/g for Pb2+ and 21.45
mg/g for Cd2+. The adsorption processes followed the pseudo first-order kinetics model. MnO2-loaded D301 resin has been shown to
have a potential to be used as an e ective adsorbent for simultaneous removal of lead and cadmium ions from aqueous solution. 相似文献
997.
998.
Occurrence of antibiotics in water, sediments, aquatic plants, and animals from Baiyangdian Lake in North China 总被引:21,自引:0,他引:21
This study investigated the presence and distribution of 22 antibiotics, including eight quinolones, nine sulfonamides and five macrolides, in the water, sediments, and biota samples from Baiyangdian Lake, China. A total of 132 samples were collected in 2008 and 2010, and laboratory analyses revealed that antibiotics were widely distributed in the lake. Sulfonamides were the dominant antibiotics in the water (0.86-1563 ng L−1), while quinolones were prominent in sediments (65.5-1166 μg kg−1) and aquatic plants (8.37-6532 μg kg−1). Quinolones (17.8-167 μg kg−1) and macrolides [from below detection limit (BDL) to 182 μg kg−1] were often found in aquatic animals and birds. Salvinia natans exhibited the highest bioaccumulation capability for quinolones among three species of aquatic plants. Geographical differences of antibiotic concentrations were greatly due to anthropogenic activities. Sewage discharged from Baoding City was likely the main source of antibiotics in the lake. Risk assessment of antibiotics on aquatic organisms suggested that algae and aquatic plants might be at risk in surface water, while animals were likely not at risk. 相似文献
999.
施氮量及抑制剂配比对双季稻生长期温室气体排放的影响 总被引:2,自引:0,他引:2
采用静态箱-气相色谱法研究了南方稻田不同施氮量及抑制剂配比对双季稻生长期内CH4、N2O和CO2排放的影响。结果表明,双季稻田施氮与抑制剂配合施用的CH4、N2O和CO2总排放量明显低于对照(常规施肥),其中CH4总排放量降低了7.6%~36.4%,N2O降低了25.8%~29.9%,CO2降低了17.7%~30.4%。早稻收获后各处理土壤NH4^+-N和NO3^--N含量存在明显差异,添加抑制剂处理的土壤NH4^+-N含量均高于对照,增幅为25.1%~77.0%,土壤NO3^--N以早稻移栽前基施N 240 kg·hm^-2配合12‰NAM和晚稻追施N 30 kg·hm^-2的处理比对照降低了61.8%(P﹤0.05),而基施N 330 kg·hm^-2配合8‰NAM处理可能因早稻施氮过量反而高于对照。表明合理的施氮量及抑制剂添加比例能有效提高土壤中NH4^+-N含量,减少NO3^--N残留,从而达到降低双季稻期间稻田温室气体排放的效果,为进一步利用抑制剂(NAM)与N、P、K化肥合理配比并形成复配肥,构建南方双季稻田温室气体减排的新型施肥模式提供技术支撑。 相似文献
1000.
石灰与磷肥对籽粒苋吸收镉的影响 总被引:9,自引:0,他引:9
籽粒苋(Amaranthus hypochondriacus L.)是我国广泛栽种的牧草,但具有富集重金属Cd的特性,探讨减少其吸收镉的方法技术,可以降低人畜受害风险.研究利用温室盆栽方法,比较了施用磷肥和石灰对降低籽粒苋Cd吸收量的影响.于含镉5 mg·kg-1的污染菜园土中,以粉末形式加入3 g·kg-1 Ca(OH)2,或以液态形式加入磷肥(0.326 g·kg-1 Ca(H2PO4)2)至P浓度80 mg·kg-1,该施用量为农业应用常规水平.播种籽粒苋,于60 d后收获,测定相关参数.结果表明,施用石灰使土壤pH上升1.7单位,土壤有效Cd下降至极低水平,从而大幅降低籽粒苋Cd吸收量,较对照下降约56%,但施石灰也使土壤供磷量下降,使籽粒苋的生物量也减少了约一半.施用石灰后,土壤的Ca与K供应量以及籽粒苋体内Ca与K含量均明显增加,Ca、K与Cd形成的竞争吸收也是施用石灰后籽粒苋Cd含量下降的一个原因.本地菜同土含有较高的有效磷,以常规农业磷肥施用量施用磷肥对籽粒苋吸收Cd没有明显影响,对生物量也没有明显影响,但适当提高施用量预期会有一定的效果.因而,对广州地区菜园土,使用合理的石灰施用量,可有效降低籽粒苋Cd吸收量. 相似文献