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   183篇
  免费   16篇
  国内免费   61篇
安全科学   7篇
废物处理   13篇
环保管理   11篇
综合类   119篇
基础理论   43篇
污染及防治   47篇
评价与监测   3篇
社会与环境   8篇
灾害及防治   9篇
  2024年   1篇
  2023年   2篇
  2022年   10篇
  2021年   5篇
  2020年   8篇
  2019年   13篇
  2018年   11篇
  2017年   11篇
  2016年   13篇
  2015年   10篇
  2014年   11篇
  2013年   17篇
  2012年   22篇
  2011年   26篇
  2010年   16篇
  2009年   4篇
  2008年   4篇
  2007年   10篇
  2006年   11篇
  2005年   6篇
  2004年   6篇
  2003年   4篇
  2002年   2篇
  2001年   3篇
  2000年   1篇
  1999年   3篇
  1998年   4篇
  1997年   3篇
  1996年   4篇
  1995年   3篇
  1994年   5篇
  1993年   6篇
  1992年   4篇
  1979年   1篇
排序方式: 共有260条查询结果,搜索用时 20 毫秒
181.
曝气强度对城市污泥重金属生物沥滤过程的影响研究   总被引:1,自引:1,他引:0  
以氧化亚铁作为底物,氧化亚铁硫杆菌(Thiobacillusferrooxidans)为主要沥滤微生物,在底物投配比为10 g/L,温度为25℃,污泥浓度为123g/L的条件下,采用5种不同曝气强度对桂林城市污泥中重金属进行生物沥滤试验。结果表明,生物沥滤的经济曝气强度宜控制在每升污泥0.4L/(min·L),沥滤3 d后,污泥中超标元素Cu、Zn和Cd的去除率分别达到62.53%、67.80%和54.63%,沥滤处理后污泥中残余重金属含量符合污泥农用的国家标准。  相似文献   
182.
稀盐酸预处理对稻草厌氧消化的影响   总被引:3,自引:2,他引:1  
为探明稀酸预处理对稻草厌氧消化的影响,采用不同浓度的稀盐酸溶液对稻草进行了浸泡预处理,并在完全混合厌氧消化条件下,研究了稻草厌氧发酵过程中的产气量、甲烷含量,发酵液中COD、pH值及挥发性脂肪酸(VFA)的变化情况.结果表明,增大稀盐酸溶液浓度会提高稻草厌氧消化反应的效果.分别经4%、8%和12%的稀盐酸溶液浸泡预处理...  相似文献   
183.
Jin Y  Zheng S  Pu Y  Shu L  Sun L  Liu W  Fu Z 《Chemosphere》2011,82(3):398-404
Cypermethrin (CYP), a widely used Type II pyrethroid pesticide, is one of the most common contaminants in the freshwater aquatic system. We studied the effects of CYP exposure on the induction of hepatic oxidative stress, DNA damage and the alteration of gene expression related to apoptosis in adult zebrafish. Hepatic mRNA levels for the genes encoding antioxidant proteins, such as Cu/Zn-Sod, Mn-Sod, Cat, and Gpx, were significantly upregulated when zebrafish were exposed to various concentrations of CYP for 4 or 8 days. In addition, the main genes related to fatty acid β-oxidation and the mitochondrial genes related to respiration and ATP synthesis were also significantly upregulated after exposure to high concentrations (1 and 3 μg L−1) of CYP for 4 or 8 days. Moreover, in a comet assay of zebrafish hepatocytes, tail DNA, tail length, tail moment and Olive tail moment increased in a concentration-dependent manner. The significant induction (p < 0.01) of all four parameters observed with CYP concentrations of 0.3 μg L−1 or higher suggests that heavy DNA damage was induced even at low levels. Furthermore, several apoptosis- related genes, such as p53, Apaf1 and Cas3, were significantly upregulated after CYP exposure, and Bcl2/Bax expression ratio decreased, especially in groups treated with 1 and 3 μg L−1 CYP for 8 days. Taken together, our results suggested that CYP has the potential to induce hepatic oxidative stress, DNA damage and apoptosis in zebrafish. This information will be helpful in fully understanding the mechanism of aquatic toxicology induced by CYP in fish.  相似文献   
184.
以Fe(Ⅲ)-酒石酸配合物体系光化学过程中产生的Fe(Ⅱ)和.OH为主要检测对象,探讨了Fe(Ⅲ)-酒石酸配合物体系光化学反应的基本规律及影响因素。结果表明,体系的光化学过程能产生Fe(Ⅱ)和.OH;产生Fe(Ⅱ)的速率远高于产生.OH的速率;Fe(Ⅱ)生成浓度在pH 3.50时最大,.OH则在pH 3.00时最大;配合物的光化学过程中会伴随pH的升高;在照度为3.6×103Lux的日光灯照射下,Fe(Ⅲ)-酒石酸盐配合物初级光解的速率常数为2.1×10-3S-1;Fe(Ⅱ)是高价重金属的主要还原剂,.OH是有机物的主要氧化剂。  相似文献   
185.
污泥回流分离工艺(RSSP)除磷脱氮试验研究   总被引:1,自引:1,他引:0  
介绍了一种新型的脱氮除磷工艺——回流污泥分离工艺(return sludge separate process),及其运行情况。该工艺在传统的厌氧缺氧好氧(A2/O)的模式下,针对硝酸盐对厌氧释磷的抑制问题进行改进,提出回流污泥的气浮浓缩分离方案,以提高系统的脱氮除磷效果。研究结果表明,在进水COD为250~400 mg/L,NH+4-N为30~45 mg/L,PO3-4-P为8~10 mg/L左右时,该工艺对NH+4-N和PO3-4-P的去除率分别可达79.3%和95%。该系统与A2/O的平行比较数据表明,该系统能够提高氮磷综合处理效率,解决A2/O处理工艺中存在无效释磷和硝酸根抑制问题。  相似文献   
186.
Chromium (Cr) is one of the most serious pollutants in aquatic systems. This study examined the relationship between the toxic effects of Cr on the freshwater alga Chlorella vulgaris and phosphorus (P) availability on the algal physiology and ultrastructure. Cr inhibited C. vulgaris growth in a concentration- and time-dependent manner, and its inhibitory effect was related to the P concentration. In a low-P medium, Cr showed approximately 2.2–3.7-fold stronger toxicity than in a high-P medium. Cr was absorbed into the algal body where it disrupted the chloroplast structure and decreased the chlorophyll content. However, Cr had a weaker chlorophyll inhibitory ability and destructive power against the chloroplasts in the high-P medium than in the low-P medium due to the partial blockage of Cr absorption in high P-medium. Cr exposure also changed the metal ion and anion absorption profiles, which was also closely related to the concentration of P. Cr treatment increased the volume of the vacuole, and the larger vacuole reduced the space available for chloroplasts, as based on optical and electron microscopy results, but a higher P availability could alleviate this damage. These results suggest that high P alleviated the toxicity of Cr by decreasing Cr absorption and increasing the absorption of beneficial ions. It is, therefore, necessary to consider the phosphorus availability when the toxicity of metal compounds is evaluated.  相似文献   
187.
介绍了采油厂生产巡检在线信息管理系统的依托技术、管理网络、硬件构成、软件组成、试验情况和应用效果.该系统依托GPS和GIS等技术,采用了B/S结构、JAVA/JSP技术,能够准确及时显示巡检员的巡检路径,巡检结果从网上数据报表和电子地图及时看到,实现了实时监控,保障了油(水)井安全生产.  相似文献   
188.
To control the emission of halides into the environment, an experiment on the nonthermal plasma decomposition of the halides CF4, CHF3, C2HCl3, and CHClF2 was conducted in a wire-in-tube corona reactor. It was found that the decomposition of C2HCl3 and CHClF2 was easy compared with the decomposition of CF4 and CHF3. With the addition of H2 in N2 gas, the decomposition ratio of CF4, C2HCl3, and CHClF2 increased. In contrast, the decomposition ratio of CHF3 in a hydrogen-rich atmosphere was lower than that in an N2 atmosphere. It was demonstrated that the yields of HF and/or HCl formed during halide decomposition clearly increased in the presence of H2 in N2 gas. Furthermore, in order to prevent the production of unwanted products from halide decomposition, a combination of plasma decomposition and in situ alkaline absorption was devised by coating a layer of Ca(OH)2 onto the surface of the grounding electrode. It was demonstrated that the Ca(OH)2 sorbent played an effective role as a scavenger, participating in halide decomposition by capturing reaction products such as HCl and HF, therefore resulting in increased halide decomposition.  相似文献   
189.
江西九江市水环境综合控制规划研究   总被引:1,自引:1,他引:0  
从‘水污染控制区’系统划分出发,计算九江水环境容量大小及分布特征:提出了九江市污水排放标准和经济,技术与环境三位一体的水环境综合治理方案。  相似文献   
190.
The potential harm of organic pollutants in drinking water to human health is widely focused on in the wodd; more and more pollutants with genotoxic substances are released into the aquatic environment. Water source samples were collected from 7 different localities of Nanjing City. The potential genotoxicity of organic extracts from drinking water sources were investigated by means of the comet assay in human peripheral lymphocytes. The results showed that all the organic extracts from all the water source samples could induce DNA damages of human peripheral blood lymphocytes at different levels. A significant difference (P 〈 0.01) was observed when compared with the solvent control, The DNA damage increased with the increase of the dosage of the original water source. Significant differences of DNA damage were observed in different drinking water sources, as shown by the multiple comparisons analysis at the dosage of 100x; the degree of DNA damage treated by Hushu waterworks (at town level) was the most serious, the arbitrary units (AU) was 141.62±6.96, however, that of Shangyuanmen waterworks (at city level) was only 109.64±2.97. The analysis also revealed that the genotoxicity of town's water sources was higher than that of the city. The results demonstrated that the comet assay can be successfully applied to the genotoxicity monitoring programs of drinking water sources.  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