全文获取类型
收费全文 | 290篇 |
免费 | 22篇 |
国内免费 | 51篇 |
专业分类
安全科学 | 71篇 |
废物处理 | 2篇 |
环保管理 | 35篇 |
综合类 | 145篇 |
基础理论 | 57篇 |
污染及防治 | 15篇 |
评价与监测 | 9篇 |
社会与环境 | 18篇 |
灾害及防治 | 11篇 |
出版年
2023年 | 2篇 |
2022年 | 8篇 |
2021年 | 12篇 |
2020年 | 4篇 |
2019年 | 13篇 |
2018年 | 12篇 |
2017年 | 2篇 |
2016年 | 13篇 |
2015年 | 10篇 |
2014年 | 11篇 |
2013年 | 17篇 |
2012年 | 24篇 |
2011年 | 17篇 |
2010年 | 24篇 |
2009年 | 16篇 |
2008年 | 16篇 |
2007年 | 41篇 |
2006年 | 24篇 |
2005年 | 22篇 |
2004年 | 14篇 |
2003年 | 15篇 |
2002年 | 7篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 1篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 3篇 |
排序方式: 共有363条查询结果,搜索用时 15 毫秒
351.
352.
Aluminum salt coagulants were used prevalently in various water works.In this article,the effects of filtration on residual aluminum concentration and species distribution were researched by determining the concentration of diiferent aluminum species before and after single layer filter,double layer filter,and membrane filtration units.In the research,size exclusion chromatography(SEC)was used to separate colloidal and soluble aluminum,ion exchange chromatography(IEC)was used to separate organic and inorganic aluminum, and inductivity coupled plasma-atomic emission spectrometry(ICP-AES)was used to determine the aluminum concentration.The results showed that the rapid filtration process had the ability of removing residual aluminum from coagulant effluent water,and that double layer filtration was more effective in residual aluminum removal than single layer filtration,while nano filtration was more effective than micro filtration.It was found that when the residual aluminum concentration was below 1mg/L in sediment effluent,the residual aluminum concentration in treated water was above 0.2 mg/L.The direct rapid filtration process mainly removed the suspended aluminum.The removal of soluble and colloidal aluminum was always less than 10% and the natural small particles that adsorbed the amount of soluble or small particles aluminum on their surface were difficult to be removed in this process.Micro filtration and nano filtration were good technologies for removing aluminum;the residual aluminum concentration in the effluent was less than 0.05 mg/L. 相似文献
353.
分离获得4株能利用乳酸作为唯一碳源分别进行好氧生长和厌氧生长的光合细菌菌株,对其无细胞抽提液进行透析和乳酸转化为丙酮酸能力的测定.结果表明,这4株光合细菌在好氧和厌氧条件下对乳酸的代谢机制是不同的.对筛选获得的高乳酸转化能力的S1菌株的进一步研究表明,黑暗好氧条件下,S1菌株的乳酸代谢能力与生长呈正相关关系;而光照厌氧条件下,乳酸代谢酶的合成滞后于生长.图5表1参10 相似文献
354.
关于新疆环境应急能力建设的探讨 总被引:3,自引:0,他引:3
阐述了新疆环境应急能力建设的重要性,对新疆环境应急现状中存在的问题进行了分析,提出了加强环境应急能力建设的几点建议。 相似文献
355.
高职教育从起始阶段开始就预示要培养大批技能型人才,不可否认职业院校在发展过程中出现了一些问题,特别是学生职业能力培养与用人单位岗位要求存在脱节。高职院校正在如何有效突出学生的职业能力这方面努力寻求突破口,在教学目标和方法、校内实训环境和校外实训基地建设、课程创新改革、“双师型”教师和高层次人才引进机制方面探索一条有效出路。 相似文献
356.
357.
PHBV泡沫吸油材料的制备及吸油性能研究 总被引:3,自引:0,他引:3
以PHBV为基材 ,在不同的助剂条件下采用真空冷冻干燥制备了几种PHBV泡沫吸油材料 ,并进行了吸油性能的比较。实验结果表明 :以三氯甲烷和乙基纤维素为助剂制备的PHBV泡沫吸油材料的吸油率、二次吸油率随着助剂量的增加而有所提高 ,而以乙酸纤维素为助剂制备的PHBV泡沫吸油材料的吸油率、二次吸油率随着助剂量的增加而有所降低 ,三者保油率的变化不明显。当达到最佳配比时 ,三种助剂制备的PHBV泡沫在 2 6℃原油下的吸油率可达 2 0倍 ,在 17℃原油下的吸油率可达 30倍。从吸油性能、成本和环保等方面综合考虑 ,以乙酸纤维素作为助剂的制备方法为最佳 相似文献
358.
Increasing attention has been paid to phosphate-accumulating organisms(PAOs)for their important role in biological phosphorus removal.In this study,microbial communities of PAOs cultivated under different carbon sources(sewage,glucose,and sodium acetate) were investigated and compared through culture-dependent and culture-independent methods,respectively.The results obtained using denaturing gradient gel electrophoresis(DGGE)of polymerase chain reaction-amplified 16S rDNA fragments revealed that the diversity of bacteria in a sewage-fed reactor(1#)was much higher than in a glucose-fed one(2#)and a sodium acetate-fed one(3#);there were common PAOs in three reactors fed by different carbon sources.Five strains were separated from three systems by using a phosphate- rich medium;they were from common bacteria isolated and three isolates could not be found in DGGE profile at all.Two isolates had good phosphorus removal ability.When the microbial diversity was studied,the molecular biological method was better than the culture-dependent one.When phosphorus removal characteristics were investigated,culture-dependent approach was more effective. Thus a combination of two methods is necessary to have a comprehensive view of PAOs. 相似文献
359.
森林凋落物对土壤酸化缓冲作用的初步研究 总被引:6,自引:0,他引:6
阔叶树木荷凋落物的灰分元素含量以及分解速率大大高于针叶树杉木凋落物。相比之下,木荷凋落物具有较高的缓冲酸化的潜在能力。覆盖木荷凋落物的土壤,其下渗液盐基含量和PH值与对照相比显著较高,而土壤本身的盐基饱和度和有机质含量也显著较高,土壤酸度和Al/Ca显著较低,即太荷凋落物对土壤酸化有较高的缓冲能力,而杉木凋落物则不然。 相似文献
360.
GONG Chun-ming 《环境科学学报(英文版)》2007,19(8):1014-1019
Various kinds of pathogenic bacteria derived from the intestinal tract of animals exist in compost material like cow dung.In order to sterilize the pathogenic bacteria completely in compost material,the cow dung was put into a heat treatment machine in pilot plan, and harmless condition in short time was examined.The results indicated,pathogenic indicator bacteria such as coliform bacteria, fecal coliform,Escherichia coli and salmonella were all 10~6 cfu/g dw at the beginning,died rapidly when cow dung temperature rose to above 50℃,and not detected at 54-68℃for 6-24 h heat treatment.Coliform bacteria and salmonella in heated cow dung were not detected by re-growth culture and enrichment culture examination.Moreover,it was hardly influenced on the fermentation ability of composting microbe,organic decomposition bacteria.During heat treatment,the mesophile decreased rapidly and the thermophile stabilized or increased,and the most of composting microbe were bacillus in cow dung by fluorescence microscope,this indicated that bacillus was dominator and composting microbe in composting process. 相似文献