全文获取类型
收费全文 | 1557篇 |
免费 | 139篇 |
国内免费 | 489篇 |
专业分类
安全科学 | 230篇 |
废物处理 | 126篇 |
环保管理 | 130篇 |
综合类 | 1117篇 |
基础理论 | 285篇 |
污染及防治 | 193篇 |
评价与监测 | 85篇 |
社会与环境 | 12篇 |
灾害及防治 | 7篇 |
出版年
2024年 | 17篇 |
2023年 | 29篇 |
2022年 | 49篇 |
2021年 | 67篇 |
2020年 | 43篇 |
2019年 | 66篇 |
2018年 | 41篇 |
2017年 | 60篇 |
2016年 | 81篇 |
2015年 | 85篇 |
2014年 | 137篇 |
2013年 | 97篇 |
2012年 | 100篇 |
2011年 | 110篇 |
2010年 | 78篇 |
2009年 | 99篇 |
2008年 | 99篇 |
2007年 | 70篇 |
2006年 | 88篇 |
2005年 | 65篇 |
2004年 | 51篇 |
2003年 | 74篇 |
2002年 | 67篇 |
2001年 | 70篇 |
2000年 | 54篇 |
1999年 | 40篇 |
1998年 | 44篇 |
1997年 | 41篇 |
1996年 | 41篇 |
1995年 | 38篇 |
1994年 | 43篇 |
1993年 | 30篇 |
1992年 | 26篇 |
1991年 | 21篇 |
1990年 | 31篇 |
1989年 | 26篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
排序方式: 共有2185条查询结果,搜索用时 15 毫秒
881.
针对300 MW发电机组内冷水系统运行中铜含量长期超标问题,分析产生原因,提出了采用添加缓蚀剂和离子交换处理技术的解决方案。改造结果表明:内冷水系统水质已符合国家标准,有效地减缓了铜线棒的腐蚀,大大提高了内冷水的绝缘性能。 相似文献
882.
Cu2+-Mn2+-H2O2体系催化氧化降解罗丹明B 总被引:6,自引:3,他引:3
研究了Cu2+-Mn2+-H2O2体系催化氧化降解染料罗丹明B的效果。实验结果表明,Cu2+-Mn2+-H2O2体系的罗丹明B降解率比H2O2体系、Mn2+-H2O2体系和Cu2+-H2O2体系有显著提高,反应120rain后罗丹明B降解率接近100%。对于Cu2+-Mn2+-H2O2体系,最佳罗丹明B降解条件:溶液pH为5,反应温度为45℃,质量浓度为10mg/L的罗丹明B溶液体积100mL,浓度为0.01mol/L的硫酸铜溶液加入量5.0mL,浓度为0.01moVL的硫酸锰溶液加入量3.0mL,体积分数为30%的H2O2溶液加入量1.5mL。在此条件下罗丹明B降解的反应速率常数最大,为0.04228min-1,其拟合相关系数为0.99912。罗丹明B降解符合一级动力学模型。 相似文献
883.
Impacts of soil organic matter, pH and exogenous copper on sorption behaviorof norfloxacin in three soils 总被引:3,自引:0,他引:3
ZHANG Jie LI Zhaojun GE Gaofei SUN Wanchun LIANG Yongchao WU Laosheng 《环境科学学报(英文版)》2009,21(5):632-640
Norfloxacin (Nor) sorption and the factors (soil organic matter (SOM), pH, and exogenous copper (Cu) influencing the sorption were investigated in a black soil (soil B), a fluvo-aquic soil (soil F), and a red soil (soil R). With increasing of Nor concentrations, sorption amount of norfloxacin increased in both the bulk soils and their SOM-removed soils, but the sorption capacity in SOM-removed soils was higher than that of their corresponding bulk soils, indicating that the process of norfloxacin sorption in soil was influenced by the soil properties including SOM. The sorption data in all bulk soils and SOM-removed soils were fitted to Freundlich and Langmuir models. The correlation coefficients suggested that the experimental data fitted better to Freundlich equation than to Langmuir equation. Furthermore, the data from soil F and SOM-removed F could not be described by Langmuir equation. The norfloxacin sorption amount decreased in soil B and soil F, whereas it increased in soil R as solution pH increased. The maximum KD and KOC were achieved in soil R when the equilibrium solution pH was 6. And the norfloxacin sorption was also influenced by the exogenous Cu2+ ions, which depended on the soil types and Cu2+ concentrations. With increasing of Cu2+ concentrations in solution, generally, sorption amount, KD and KOC for norfloxacin in soils increased and were up to a peak at 100 mg/L Cu2+, and then the sorption amount decreased regardless of norfloxacin levels. 相似文献
884.
885.
886.
铜、铅在车前草中的亚细胞分配 总被引:2,自引:1,他引:1
通过盆栽试验研究了四川荥经县宝贝凼(BBD)和泸县(LX)车前草在铜(Cu)、铅(Pb)单元素污染处理下叶片中Cu和Pb的亚细胞分布特征.结果表明,BBD车前草生物量和富集Cu、Pb的能力均明显高于LX.不同处理下,BBD车前草各亚细胞组分中Cu和Pb含量变化特征为细胞器最高,细胞壁次之,胞液最低;;LX车前草各亚细胞组分中Cu和Pb含量变化特征为细胞壁最高,细胞器次之,胞液最低.BBD和LX车前草亚细胞各组分Pb含量均高于Cu.细胞器是细胞最重要的光合作用和呼吸作用的场所,结合Cu、Pb的能力较强,细胞壁对进入植物体内的Cu和Pb有极强的束缚作用,这可能是车前草能够解毒的重要原因. 相似文献
887.
Mechanism of Cu(Ⅱ) adsorption inhibition on biochar by its aging process 总被引:13,自引:0,他引:13
Biochar exposed in the environment may experience a series of surface changes, which is called biochar aging. In order to study the effects of biochar aging on Cu(Ⅱ) adsorption, we analyzed the surface properties before and after biochar aging with scanning electron microscopy(SEM) coupled to an energy-dispersive X-ray spectrometer(EDX) and diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS), and then explored the influence of the aging process on Cu(Ⅱ) adsorption by batch experiments. After the aging process, the oxygen concentration, phenolic hydroxyl groups, aromatic ethers and other oxygen-containing functional groups on the biochar surface increased, while carboxyl groups slightly decreased. Thus, over a range of pH, the cation exchange capacity(CEC) and adsorption capacity of Cu(Ⅱ) on the aged biochar were smaller than those of new biochar,indicating that when biochar is incubated at constant temperature and water holding capacity in the dark, the aging process may inhibit Cu(Ⅱ) adsorption. Meanwhile, the dissociation characteristics of oxygen-containing functional groups changed through the aging process, which may be the mechanism by which the biochar aging process inhibits the Cu(Ⅱ) adsorption. Carboxyl groups became more easily dissociated at low pH(3.3–5.0),and the variation of maximum adsorption capability(qm) of Cu(Ⅱ) on the old biochar was enlarged. Phenolic hydroxyl groups increased after the aging, making them and carboxyl groups more difficult to dissociate at high pH(5.0–6.8), and the variation of qmof Cu(Ⅱ) on the aged biochar was reduced. 相似文献
888.
889.
基于相似理论和溃决侵蚀原理,进行不同加筋密度条件下尾矿坝洪水漫顶破坏模
型试验,探析了筋带密度对尾矿坝漫顶破坏影响规律。试验结果发现:①随着筋带密度
的增加显著提升了尾矿坝的力学强度,但也导致了坝体内的浸润线升高;②筋带密度的
增加使溃口由“Y”型逐渐向“H”型转变;③筋带密度的增加阻滞了漫坝破坏的发展,
坝体位移及内部应力变化量明显减小;④增加筋带密度提高了坝体的抗冲刷能力,减弱
了洪水对蚀沟两岸尾砂的拉拽作用,保证了蚀沟两翼坝体的稳定;⑤随着筋带密度增加
,可有效减小坝体位移和溃口深度、宽度的发展,当筋带超过2层后,筋带层数的增加
对坝体溃口宽、深基本无影响。研究成果深入探析了筋带密度对漫顶破坏影响规律,在
尾矿坝加筋研究方面提供了科学依据。 相似文献
890.
为弥补传统基于GPS/GNSS的单点监测方式无法反映尾矿坝整体变形的局限性,提出1种结合坝坡现有位移监测系统的无人机尾矿坝边坡表面变形监测方法.利用单镜头轻小型多旋翼无人机和计算机视觉技术对尾矿坝的空间三维地理信息进行数据采集与重建;基于设置在坝坡表面的位移人工监测点(水泥桩)对多期尾矿坝点云数据进行配准;通过对不同时... 相似文献