全文获取类型
收费全文 | 542篇 |
免费 | 15篇 |
国内免费 | 6篇 |
学科分类
工业技术 | 563篇 |
出版年
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2018年 | 4篇 |
2017年 | 6篇 |
2016年 | 11篇 |
2015年 | 10篇 |
2014年 | 17篇 |
2013年 | 30篇 |
2012年 | 49篇 |
2011年 | 70篇 |
2010年 | 56篇 |
2009年 | 26篇 |
2008年 | 41篇 |
2007年 | 44篇 |
2006年 | 33篇 |
2005年 | 31篇 |
2004年 | 16篇 |
2003年 | 19篇 |
2002年 | 17篇 |
2001年 | 16篇 |
2000年 | 5篇 |
1999年 | 10篇 |
1998年 | 8篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1994年 | 8篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1984年 | 1篇 |
排序方式: 共有563条查询结果,搜索用时 15 毫秒
1.
酸浸高岭土制备PAC时连续搅拌反应器容积计算 总被引:2,自引:0,他引:2
酸浸反应器是高岭土制备聚合氯化铝(PAC)的重要设备。基于连续搅拌反应器具有操作简便、产品质量稳定和环境清洁等优点,文章研究了高岭土酸浸连续搅拌反应器容积的计算方法。在相同条件下,采用连续搅拌反应器较为经济。 相似文献
2.
3.
PAC-自生动态膜生物反应器处理生活污水的研究 总被引:3,自引:0,他引:3
向由孔径为56μm的普通工业滤布组成的膜生物反应器中投加不同量的粉末活性炭,对恒通量下的单周期运行情况进行了考察,并对被污染的动态膜表面和截面进行了扫描电镜观察。结果表明,较佳的PAC投量约为2g/L。在PAC投量为2g/L时,其运行周期(15d)为不投加PAC时(6d)的2.5倍,反应器中占优势的污泥平均粒径(100μm)也较不投加PAC时的(80μm)大。经扫描电镜分析可知,未投加PAC时膜孔隙间的凝胶层是造成膜污染的主要因素;投加2异/L的PAC时膜表面的滤饼层是造成膜污染的主要因素,其膜污染物易于清洗去除,经水力清洗和刷子刷洗后膜通量可基本恢复,再用0.5%的NaClO溶液浸泡12h后膜通量可完全恢复。 相似文献
4.
铝盐一级强化处理城市污水的正交试验 总被引:9,自引:0,他引:9
为研究一级强化处理城市污水的最佳工艺条件和各种因素对处理效果的影响,采用Al2(SO4)3和PAC分别与非离子、阴离子、弱阳离子的高分子助凝剂配合,进行了6种药剂组合的正交试验。结果表明,混凝剂投量是出水水质最主要的影响因素,在优化条件下,一级强化工艺对COD的去除率达到60%,出水COD为150mg/L左右;对TP的去除率由铝盐混凝剂的投量决定,出水TP<1mg/L,并可随混凝剂投量的继续增加而降低。高分子助凝剂能有效提高Al2(SO4)3的除磷效果,是影响出水TP的第二重要因素,但PAC系列是影响出水TP最小的因素。总之,Al2(SO4)3 高分子助凝剂与PAC 高分子助凝剂两个系列对COD的去除效果差别不大;但是,Al2(SO4)3 高分子助凝剂系列除磷效果更好。 相似文献
5.
6.
p-Nitrophenol removal by combination of powdered activated carbon adsorption and ultrafiltration - comparison of different operational modes 总被引:1,自引:0,他引:1
Ultrafiltration is classified as a low-pressure membrane technology which effectively removes particulate matter and microorganisms and to a certain extent dissolved organic matter (15-25%) and colour. The technology has been optimized and is becoming competitive compared to conventional processes for larger scale plant capacities. In combination with activated carbon it is an effective barrier regarding the removal of synthetic organic chemicals. Growing interest in ultrafiltration raises the question of better usage of the adsorption capacity of powdered activated carbon (PAC) used in combination with this low-pressure membrane technique. This paper presents a pilot plant study of different PAC dosing procedures within a combined hybrid membrane IN/OUT process for removal of p-nitrophenol (PNP) from water (c(0)=1mg/L) under real case conditions (e.g. usage of the same module for the whole duration of the experiment, backwashing with permeate water, no separate saturation of the membrane with substance without presence of carbon). p-Nitrophenol was chosen as an appropriate test substance to assess the efficiency of different operation modes. Dead-end and cross-flow filtration were compared with respect to different PAC dosing procedures: continuous dosing into a continuously stirred tank reactor (CSTR) in front of the module and direct dosing into the pipe in front of the module (continuous, single-pulse and multi-pulse dosing). There was no advantage in cross-flow mode over dead-end referring to PNP concentration in the permeate. Relating to the carbon dosing procedure, the best results were obtained for continuous PAC addition. The option of dosing directly into the pipe has the advantage of no additional tank being necessary. In the case of single-pulse dosing, the formation of a carbon layer on the membrane surface was assumed and an LDF model applied for a simplified estimation of the "breakthrough behaviour" in the thus formed "PAC filter layer". 相似文献
7.
粉末活性炭在水体中强制分散及其作用研究 总被引:1,自引:1,他引:1
探讨了水处理中粉末活性炭投加的基本方法,针对粉末活性炭颗粒间相互吸附自凝聚现象,提出强制分散技术应用于粉末活性炭投加工艺,从而提高了粉末活性炭吸附技术处理受污染原水的效率。 相似文献
8.
9.
《Food Control》2017
This work describes a multiplex ligation-dependent probe amplification (MLPA) technique for the simultaneous detection of five food allergens: sunflower, poppy, flaxseed, sesame and soy. Species-specific MLPA half-probes were designed to detect the DNA from the targeted species. Ligated probes were amplified by polymerase chain reaction (PCR) and amplicons were detected using capillary electrophoresis. The specificity of the MLPA system was assessed against DNA from more than 50 plant and animal species. The limit of detection (LOD) of the assay was determined to be 10 mg kg−1in a model cookie experimentally spiked with different concentrations of the target species. The applicability of the MLPA was demonstrated through the analysis of 56 different commercial products (breads, pastries, cereals, chocolates, drinks, etc.), evidencing the presence of one or more undeclared allergenic ingredients in some of the tested samples. Real-time PCR assays were also performed to confirm and complement MLPA results. The MLPA technique has proved as a qualified screening tool for determining the presence of low amounts of sunflower, poppy, flaxseed, sesame and soy in processed foods. 相似文献
10.
采用含邻苯二甲酸二(2-乙基己基)酯(DEHP)的试验水样模拟城市取水水源发生DEHP水污染事故,测定粉末活性炭(PAC)对水样中DEHP的吸附性能,考察PAC炭种、吸附时间、DEHP初始浓度和PAC投加量等因素对DEHP的吸附量和脱除率的影响。试验结果表明:木屑PAC具有较大的比表面积,对DEHP具有良好的吸附效果,适用于DEHP水污染的应急处理。应急处理一般的DEHP水污染事故,DEHP污染浓度超标10~30倍时,PAC吸附DEHP的最佳条件为:吸附时间120 min,PAC投加量为20~80 mg/L,PAC对DEHP的吸附过程符合Henry等温式。 相似文献