全文获取类型
收费全文 | 312篇 |
免费 | 38篇 |
国内免费 | 143篇 |
专业分类
安全科学 | 25篇 |
废物处理 | 8篇 |
环保管理 | 21篇 |
综合类 | 314篇 |
基础理论 | 67篇 |
环境理论 | 1篇 |
污染及防治 | 36篇 |
评价与监测 | 5篇 |
社会与环境 | 8篇 |
灾害及防治 | 8篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 8篇 |
2021年 | 11篇 |
2020年 | 13篇 |
2019年 | 15篇 |
2018年 | 7篇 |
2017年 | 18篇 |
2016年 | 12篇 |
2015年 | 17篇 |
2014年 | 12篇 |
2013年 | 22篇 |
2012年 | 21篇 |
2011年 | 33篇 |
2010年 | 36篇 |
2009年 | 25篇 |
2008年 | 15篇 |
2007年 | 33篇 |
2006年 | 33篇 |
2005年 | 22篇 |
2004年 | 14篇 |
2003年 | 13篇 |
2002年 | 18篇 |
2001年 | 17篇 |
2000年 | 10篇 |
1999年 | 8篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 7篇 |
1994年 | 12篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 8篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1980年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有493条查询结果,搜索用时 46 毫秒
351.
Sedum alfredii Hance, a newly discovered hyperaccumulator, could serve as a good material for phytoremediation Cd polluted sites. Malondialdehyde (MDA), reactive oxygen species (ROS) and antioxidases (catalase (CAT); superoxide dismutase (SOD); peroxidase (POD)) in the leaf were determined when S. alfredii was treated for 15 d with various CdCl2 concentrations ranging from 0 to 800 μmol/L. The results showed that the production rate of 2′,7′-dichlorofluorescein (DCF), which is an indicator of ROS level, reached up to the maximum at 400 μmol/L CdCl2 and then declined with the increase of CdCl2 concentration, while MDA accumulation tended to increase. CAT activity was significantly inhibited at all tested CdCl2 concentrations and SOD activity was sharply suppressed at 800 μmol/L CdCl2. However, the enhancement of POD activity was observed when CdCl2 concentration was higher than 400 μmol/L. In addition, its activity increased when treated with 600 μmol/L CdCl2 for more than 5 d. When sodium benzoate, a free radical scavenger, was added, S. alfredii was a little more sensitive to Cd toxicity than that exposed to Cd alone, and the Cd accumulation tended to decline with the increase of sodium benzoate concentration. It came to the conclusions that POD played an important role during Cd hyperaccumulation, and the accumulation of ROS induced by Cd treatment might be involved in Cd hyperaccumulation. 相似文献
352.
353.
354.
稀水溶液中Cr(Ⅵ)光化学还原的研究 总被引:5,自引:2,他引:3
研究了稀水溶液中Cr(Ⅵ)的光化学还原过程,考察了·OH自由基俘获剂的种类、结构及溶液pH值对Cr(Ⅵ)还原的影响结果表明稀水溶液中Cr(Ⅵ)的还原过程分化学还原与光化学还原两步进行,前者为直接氧化还原过程,后者则经历自由基反应;·OH自由基俘获剂中羟基的数量和位置对Cr(Ⅵ)的还原均有影响,羟基α位碳上氢原子数量愈多,碳氢键强度愈小,愈有利于Cr(Ⅵ)还原;溶液pH值对Cr(Ⅵ)的还原有重要影响,随着pH值的升高,其还原率和反应速率均下降,当pH≥70时,Cr(Ⅵ)的还原基本停止 相似文献
355.
356.
Obiri S Dodoo DK Okai-Sam F Essumang DK 《Environmental monitoring and assessment》2006,118(1-3):51-63
Cyanide is a very toxic chemical that is used to extract gold from its ores. Wastewaters from gold mining companies such as
Bogoso Gold Limited (BGL) contain cyanide and other potentially toxic chemicals that have adverse effects on human beings
and aquatic organisms. This study was conducted to evaluate the human health risk assessment from exposure to free cyanide
via oral and dermal contact of surface/underground water by resident adults within the concession of Bogoso Gold Limited.
The chronic non-cancer health risk from exposure to cyanide in River Bogo Upstream is 230 and 43 (by Central Tendency Exposure
(CTE) parameters respectively). This means that approximately 230 and 43 resident adults are likely to suffer diseases related
to cyanide intoxication via oral and dermal contact respectively. For chronic exposure to River Bogo Downstream by resident
adults, the non-cancer health risks are: 0.031 and 0.57 via oral and dermal contact for CTE parameters respectively, which
also means that, the non-cancer health risks associated with cyanide intoxication is negligible as the hazard index is less
than 1.0 via oral and dermal contacts respectively. The results showed that health risk for acute exposure to cyanide by the
resident adults is very high. Hence the residents attribute most of the unexplained deaths in the communities to accidental
ingestion and dermal contact of cyanide water. 相似文献
357.
随着量子点(quantum dots,QDs)在生物标记和医学影像等领域的应用日益广泛,其环境暴露量逐渐增加,深入探讨QDs的毒性机制具有重要意义。QDs通过产生活性氧(ROS)诱发毒性效应是目前普遍接受的毒作用模式。为了探讨量子点的毒性与所诱发的ROS的种类和数量的关系,选用碲化镉量子点(CdTe QDs和CdTe/ZnS QDs),利用电子顺磁共振技术(EPR)分别测定了CdTe QDs和CdTe/ZnS QDs在无细胞体系中诱导ROS产生的种类和强度;利用EPR法、紫外可见分光光度法和荧光分光光度法分别测定了4、20和100nmol·mL-1的CdTe QDs和CdTe/ZnS QDs对超氧阴离子(·O2-)和羟基自由基(·OH)产生的促进作用。实验结果显示,CdTe QDs可诱导·O2-的产生;CdTe QDs和CdTe/ZnS QDs对·OH与·O2-的产生有明显的促进作用,且具有剂量-效应关系。研究表明,量子点可诱导和促进ROS产生,不同结构量子点对ROS的诱导和促进作用不同。 相似文献
358.
The mutualistic benefits and disadvantages of non-clavicipitaceous endophytes for their hosts are not well studied and are postulated as being distinct from free-living or pathogenic counterparts. The defensive metabolites and antioxidants produced by endophytes are postulated to be the benefits offered for the hosts. Therefore, the antimicrobial and free-radical-scavenging activities of a foliar endophyte Chaetomium globosum HYML55 isolated from Hypericum mysorense of Western Ghats, India were studied. RNA secondary structure analysis refuted the unique biotope postulation because strain HYML55 was more similar to a coprophilous strain than to endophytic strains. Ethyl acetate extract of the fungus inhibited bacteria and fungi. The extract also quenched 98.65% 1,1-diphenyl- 2-picrylhydrazyl radicals with total antioxidant capacity of 13.62 mg ascorbic acid equivalent/g. A yellow amorphous antimicrobial compound purified from the extract was identified as chaetoglobosin F, which had a minimum inhibitory concentration of 7.8–15.6 μg/mL, except against Pseudomonas aeruginosa. This is the first report on the antimicrobial activity of chaetoglobosin F and other bioactivities of any endophytes from H. mysorense. The study emphasises the inter-habitat cycling of endophytes and possible benefits of C. globosum for the host. Chaetoglobosin F is an anti-inflammatory and anti-neoplastic compound, and C. globosum HYML55 could be exploited for the industrial production of this compound. 相似文献
359.
Soumaya Kilani Inès Bouhlel Ribai Ben Afef Abdelwahed Nawel Hayder Amor Mahmoud 《毒物与环境化学》2013,95(3):415-425
The mutagenic potential of aqueous, total oligomers flavonoids (TOF), ethyl acetate and methanol extracts from tubers of Cyperus rotundus L. was assessed using Ames Salmonella tester strains TA98 and TA100, and SOS chromotest strain Escherichia coli PQ37 with and without metabolic activation (S9). None of the different extracts produced a mutagenic effect. Likewise, the antimutagenicity of the same extracts was tested using the “Ames test” and the “SOS chromotest”. Our results showed that C. rotundus extracts possess antimutagenic effects against S. typhimurium TA98 and TA100 strains towards the mutagen aflatoxin B1 (AFB1), similar to E. coli PQ37 strain against AFB1 and Nifuroxazide mutagens using the SOS chromotest assay. A free radical scavenging test was used in order to explore the antioxidant capacity of the extracts obtained from the tubers of C. rotundus. TOF, ethyl acetate and methanol extracts showed an important free radical scavenging activity towards the 1,1-diphenyl-2-picrylhydrazine (DPPH) free radical. These extracts showed an IC50 value of respectively 5, 20 and 65?µg?mL?1. The beneficial effects of TOF, ethyl acetate and methanol extracts of C. rotundus were assessed by antioxidant and antimutagenic activities. 相似文献
360.
CuCl2 does not cause Trp+ reversion in E. coli WP2. However, when the bacteria are exposed to CuCl2 and UV‐irradiated, a greater than 3‐fold enhancement of mutagenesis (compared to UV alone) is seen at 30 μMCuCl2, and significant enhancement is seen even at 3 μM. The mechanism for this comutagenic effect was studied using a restriction fragment of the E. coli gpt gene. Whereas UV or CuCl2 alone caused few strand breaks, UV + CuCl2 induced breaks at every site. This reaction was blocked by KI, a free radical scavenger. While UV alone induced alkali‐labile sites, UV+ CuCl2 induced many more such sites and altered the sequence specificity. We suggest that at least some of the comutagenic effect might be due to hydroxyl radical formed via a Fenton reaction. 相似文献