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   292篇
  免费   45篇
  国内免费   135篇
安全科学   29篇
废物处理   56篇
环保管理   26篇
综合类   213篇
基础理论   43篇
污染及防治   90篇
评价与监测   14篇
社会与环境   1篇
  2023年   8篇
  2022年   7篇
  2021年   7篇
  2020年   10篇
  2019年   6篇
  2018年   10篇
  2017年   11篇
  2016年   21篇
  2015年   21篇
  2014年   23篇
  2013年   36篇
  2012年   44篇
  2011年   33篇
  2010年   26篇
  2009年   24篇
  2008年   20篇
  2007年   13篇
  2006年   31篇
  2005年   16篇
  2004年   19篇
  2003年   22篇
  2002年   11篇
  2001年   7篇
  2000年   7篇
  1999年   9篇
  1998年   8篇
  1997年   5篇
  1996年   7篇
  1995年   3篇
  1994年   4篇
  1991年   1篇
  1986年   2篇
排序方式: 共有472条查询结果,搜索用时 265 毫秒
81.
一种有机硅改性丙烯酸防污涂料的研究   总被引:4,自引:0,他引:4  
目的通过在丙烯酸树脂分子中引入有机硅,制备一种具有低表面能的有机硅改性丙烯酸树脂CP-CC021。方法探讨合成工艺中有机硅单体和引发剂含量以及添加纳米级Si O2粒子填料对涂层性能的影响规律。结果获得了最大接触角的最佳工艺条件,添加纳米Si O2粒子增大了涂层的表面粗糙度,在涂层表面形成了大量微-纳结构状的突起,显著提高涂层的疏水性能。结论有机硅单体(VTMS)质量分数为23.0%,引发剂(AIBN)质量分数为0.50%,纳米Si O2粒子添加量(质量分数)为7.4%,得到的涂层接触角为126.1°。  相似文献   
82.
树脂膜作为DGT技术的核心部分,是影响 DGT测定的关键因素。为确保树脂吸附和洗脱实验的准确性,筛选出醋酸-盐酸混合溶液作为甲基汞溶液的保存试剂。以标液中甲基汞的吸附率为指标,比较了4种吸附树脂的基本特征及在室内标液浓度为1μg/L的条件下对甲基汞的吸附效果,筛选出吸附效果最佳的树脂TCH-95,并对TCH-95树脂胶的不同洗脱试剂进行了研究。结果表明:24h TCH-95对甲基汞的吸附率高达98.9%。且在洗脱实验中,对硫脲-盐酸混合溶液添加冰醋酸有助于提高树脂胶中甲基汞的洗脱率,其2%硫脲-0.2mol/L HCl-4%HAc混合溶液的甲基汞洗脱率为84.5%,是目前TCH-95树脂的最佳洗脱剂。  相似文献   
83.
通过静态吸附实验,研究了二甲胺在ZGSPC106型细颗粒树脂上的吸附行为,从热力学和动力学角度对吸附过程进行了分析,并用红外光谱的方法探讨了树脂吸附二甲胺的机理.结果表明,Langmuir等温方程能够很好的拟合吸附平衡数据,热力学参数表明该吸附可自发进行,且为熵增加的吸热过程,293K温度下树脂的静态饱和吸附容量为138.89mg/g(干树脂);吸附动力学符合准二级动力学模型,颗粒扩散是树脂吸附二甲胺速率的主要控制步骤.  相似文献   
84.
The adsorption of two phenols, namely, phenol and salicylic acid(SA) onto a water-compatible hypercrosslinked polymeric resin (NJ-8) were studied in terms of pseudo-second-order and first order mechanisms for chemical sorption as well as an intraparticle diffusion mechanism process. Kinetic analysis showed that the intraparticle diffusion process was the essential rate-controlling step. The activation energies of sorption have also been evaluated with the pseudo-second-order and intraparticle diffusion constants, respectively. Adsorption equilibrium data were well fitted by the Langmuir, Freundlich and Redlich-Peterson isotherms. Adsorption was exothermic and basically of a type of transition between physical and chemical character. The sorption capacity was higher for SA due to its more hydrophobic. Phenol has a higher adsorption enthalpy since it could form stronger hydrogen bonding on NJ-8.  相似文献   
85.
胞外聚合物结合磷效能的研究   总被引:3,自引:2,他引:3  
以实验SBR反应器的活性污泥为研究对象,探讨了超声波-树脂法提取EPS的方法与程序;以5种不同来源的活性污泥为研究对象,考察了EPS结合磷的效能.结果表明,超声波-树脂法分离EPS和细菌细胞的较优程序为:采用21kHz、40W超声波作用60mL污泥2min(VSS约为8000mg·L-1);然后,投加80g·g-1(以...  相似文献   
86.
Abstract

This work reports the development of a very-simple-to-construct stir-bar extraction device so called “a dumbbell-shaped stainless steel stir-bar.” The extraction device was assembled from a rolled up stainless steel net filled with an XAD-2 sorbent and a metal rod to allow the use of a magnetic stirrer during extraction. The dumbbell-shaped stainless steel stir-bar was used to extract diethyl phthalate (DEP), dibutyl phthalate (DBP), and di(2-ethylhexyl) phthalate (DEHP) before analysis by a gas chromatograph equipped with an electron capture detector (GD-ECD). Under the optimal conditions, the developed method provided a good linearity from 10.0 to 1,000.0?ng mL?1 for all three compounds. Limits of detection and limits of quantification were 9.37?±?0.29?ng mL?1 and 31.22?±?0.95?ng mL?1 for DEP, 5.73?±?0.31?ng mL?1 and 19.1?±?1.0?ng mL?1 for DBP and 3.30?±?0.06?ng mL?1 and 11.0?±?0.19?ng mL?1 for DEHP, respectively. Good recoveries in the range of 81.89?±?0.17 to 109.5?±?2.0% were achieved when the method was used to extract phthalate esters in five instant noodle and two rice soup samples.  相似文献   
87.
• Two IFAS and two MBBR full-scale systems (high COD:N ratio 8:1) were characterized. • High specific surface area carriers grew and retained slow-growing nitrifiers. • High TN removal is related to high SRT and low DO concentration in anoxic tanks. The relative locations of AOB, NOB, and DNB were examined for three different kinds of carriers in two types of hybrid biofilm process configurations: integrated fixed-film activated sludge (IFAS) and moving bed biofilm reactor (MBBR) processes. IFAS water resource recovery facilities (WRRFs) used AnodkalnessTM K1 carriers (KC) at Broomfield, Colorado, USA and polypropylene resin carriers (RC) at Fukuoka, Japan, while MBBR WRRFs used KC carriers at South Adams County, Colorado, USA and sponge carriers (SC) at Saga, Japan. Influent COD to N ratios ranged from 8:1 to 15:1. The COD and BOD removal efficiencies were high (96%–98%); NH4+-N and TN removal efficiencies were more varied at 72%–98% and 64%–77%, respectively. The extent of TN removal was higher at high SRT, high COD:N ratio and low DO concentration in the anoxic tank. In IFAS, RC with high specific surface area (SSA) maintained higher AOB population than KC. Sponge carriers with high SSA maintained higher overall bacteria population than KC in MBBR systems. However, the DNB were not more abundant in high SSA carriers. The diversity of AOB, NOB, and DNB was fairly similar in different carriers. Nitrosomonas sp. dominated over Nitrosospira sp. while denitrifying bacteria included Rhodobacter sp., Sulfuritalea sp., Rubrivivax sp., Paracoccus sp., and Pseudomonas sp. The results from this work suggest that high SRT, high COD:N ratio, low DO concentration in anoxic tanks, and carriers with greater surface area may be recommended for high COD, BOD and TN removal in WRRFs with IFAS and MBBR systems.  相似文献   
88.
改性三聚氰胺甲醛树脂的合成及性能研究   总被引:5,自引:0,他引:5  
研究了反应物配比、反应时间、反应温度、PH值对丙烯酰胺改性三聚氰胺甲醛树脂絮凝效果的影响,实验结果表明絮凝效果最佳的合成反应条件为三聚氰胺/甲醛/丙烯酰胺(质量比)=1/5(2-3),反应温度为70℃,反应时间为4h,PH值为9.0左右。  相似文献   
89.
野外便携净水器应具杀菌消毒效率高、净水时间短、使用寿命长、操作方便等功能使用要求。通过试验考察了三碘树脂和载银活性炭两种不同净水消毒工艺流程对原水处理效果。结果表明:三碘树脂材料比载银活性炭材料具有灭菌效果好、反应接触时间短、使用时间长等优势,是一类具有良好军事应用价值的野外便携净水器的净水消毒材料。  相似文献   
90.
研究了XDA-200大孔树脂对水溶液中邻苯二甲酸的吸附。结果表明XDA-200树脂对水溶液中的邻苯二甲酸吸附速度很快,30min内基本达到平衡,其后达到完全平衡的吸附进程非常缓慢。树脂对邻苯二甲酸的吸附量随质量浓度增加而增加。pH值降低,有利于邻苯二甲酸在溶液中以分子态存在,易于树脂吸附。邻苯二甲酸的吸附均满足Freundlich和Langmiur等温吸附方程。泄漏点与进水浓度和流速均有很大关系。  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