全文获取类型
收费全文 | 1520篇 |
免费 | 28篇 |
国内免费 | 110篇 |
专业分类
安全科学 | 194篇 |
废物处理 | 22篇 |
环保管理 | 141篇 |
综合类 | 920篇 |
基础理论 | 71篇 |
污染及防治 | 203篇 |
评价与监测 | 94篇 |
社会与环境 | 11篇 |
灾害及防治 | 2篇 |
出版年
2024年 | 1篇 |
2023年 | 18篇 |
2022年 | 18篇 |
2021年 | 43篇 |
2020年 | 57篇 |
2019年 | 36篇 |
2018年 | 20篇 |
2017年 | 24篇 |
2016年 | 34篇 |
2015年 | 56篇 |
2014年 | 77篇 |
2013年 | 42篇 |
2012年 | 41篇 |
2011年 | 110篇 |
2010年 | 40篇 |
2009年 | 89篇 |
2008年 | 70篇 |
2007年 | 95篇 |
2006年 | 71篇 |
2005年 | 88篇 |
2004年 | 69篇 |
2003年 | 75篇 |
2002年 | 71篇 |
2001年 | 67篇 |
2000年 | 55篇 |
1999年 | 64篇 |
1998年 | 56篇 |
1997年 | 55篇 |
1996年 | 29篇 |
1995年 | 21篇 |
1994年 | 28篇 |
1993年 | 19篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有1658条查询结果,搜索用时 15 毫秒
991.
The optimization of volume ratio (VAn/VA/VO) and nitrate recycling ratio (R) in a two-sludge denitrifying phosphorus removal (DPR) process of Anaerobic Anoxic Oxic-Moving Bed Biofilm Reactor (A2/O-MBBR) was investigated. The results showed that prolonged anaerobic retention time (HRTAn: 1.25→3.75 hr) exerted favorable effect on chemical oxygen demand (COD) removal (57.26%→73.54%), poly-β-hydroxyalkanoates (PHA) synthesis (105.70→138.12 mgCOD/L) and PO43? release (22.3→38.9 mg/L). However, anoxic retention time (HRTA) and R exhibited positive correlation with PHA utilization (43.87%-81.34%) and denitrifying phosphorus removal (DPR) potential (ΔNO3?/ΔPO43?: 0.57-1.34 mg/mg), leading to dramatical TN removal variations from 68.86% to 81.28%. Under the VAn/VA/VO ratio of 2:6:0, sludge loss deteriorated nutrient removals but the sludge bioactivity quickly recovered when the oxic zone was recovered. The sludge characteristic and microstructure gradually transformed under the dissolved oxygen (DO) control (1.0-1.5→1.5-2.0 mg/L), in terms of sludge volume index (SVI: 194→57 mL/gVSS), median-particle-size (D50: 99.6→300.5 μm), extracellular polymeric substances (EPS) (105.62→226.18 mg/g VSS) and proteins/polysaccharides (PN/PS) ratio (1.52→3.46). Fluorescence in situ hybridization (FISH) results showed that phosphorus accumulation organisms (PAOs) (mainly Cluster I of Accumulibacter, contribution ratio: 91.79%-94.10%) dominated the superior DPR performance, while glycogen accumulating organisms (GAOs) (mainly Competibacter, contribution ratio: 82.61%-86.89%) was responsible for deteriorative TN and PO43? removals. The optimal HRTA and R assembled around 5-6.5 hr and 300%-400% based on the PHA utilization and DRP performance, and the oxic zones also contributed to PO43? removal although it showed low dependence on DO concentration and oxic retention time (HRTO). 相似文献
992.
993.
周良 《环境监测管理与技术》2003,15(4):34-34
采用液上顶空气相色谱法测定地表水和废水中的4-甲基-2-戊酮。以HP-5毛细管柱分离,氢火焰离子化检测器检测,取得较好的结果。方法检测限为0.06mg/L,相对标准偏差为5%,加标回收率在82%~117%之间。 相似文献
994.
含氰尾矿充填前碱氯法处理的技术研究 总被引:1,自引:0,他引:1
应用碱氯法处理含氰废水和废矿浆的实验表明:经处理后氰化物浓度可以达到国家的《污水综合排放标准》要求。用次氯酸钙处理的效果优于漂白粉,而且成本也可以得到降低。相同浓度的废水和矿浆,后者的次氯酸钙用量要低于前者。二者的剩余氰化物浓度和次氯酸钙用量都呈对数曲线关系,回归方程都可以表示为y=a-blnx。 相似文献
995.
微电解法预处理利福平制药废水的试验研究 总被引:3,自引:0,他引:3
采用微电解法预处理利福平制药废水,并以COD去除率及色度去除率为指标考察其处理效果。试验自制了微电解柱,考察了废水pH、粒度、炭铁比、温度、反应时间等因素对废水COD和色度去除率的影响。结果表明:在常温下,进水pH为2,铁屑和焦炭的粒度均为0.6mm,铁炭比为20∶1,反应时间为120min处理效果最好。水样COD去除率达到52.0%,色度去除率达到60.0%,为后期的生化处理提供了条件。 相似文献
996.
原子吸收法测定废水中重金属,用不同的前处理方法所得到的数据结果有所不同。因此,对每种金属元素选择适当的前处理方法尤为重要。 相似文献
997.
Although major hazard industries have no legal obligations to demonstrate a good safety culture, it is an increasingly important factor for risk-based inspections. This paper describes the development and evaluation of a relatively simple method for external indicative assessment of the process safety culture in major hazard industries. As a first step, a tool was developed. Second, the tool was successfully tested in a workshop with major hazard inspectors. After this ‘proof of concept’ and a few adaptations to improve the tool, quantitative evaluation and validation were carried out with a representative sample of major hazard inspectors in the Netherlands. In this stage, the tool comprised 30 questions, of which 19 sufficiently frequent valid responses were given for the validity test. The evaluations demonstrate that without specific preparations, inspection teams can use the tool to discriminate between plants with poor or good safety cultures. That is sufficient for ranking as additional input for risk-based inspection strategies. The resulting indicative ‘scores’ for safety culture correlate meaningfully with the quality of process safety management systems and the number of (legal) non-compliances, which were identified by the inspection team at the same occasion. The use of the tool can be further improved by training inspectors, making minor adaptations of the inspection process, and broadening the scope of a few questions. It is expected that external assessments of safety culture will become increasingly important not only for inspectorates, but also for a range of other external stakeholders. 相似文献
998.
In powder handling and processing industry, location of dust emission can vary, with the suspended dust concentration assessment requiring installation of an immovable or wired equipment. For increased dust sensing, not limited by location within the facility, a portable suspended dust concentration measuring system is needed. In this study, a new method of sensing suspended dust concentration under daylight environment using the change in light extinction coefficient was developed. The method involves capturing images of the suspended dust cloud and then analyzing the light extinction coefficient. This method mitigated the environmental light scattering and absorption and eliminated the noise from the images obtained through a camera by calibration between two targets. Cornstarch, corn dust, and sawdust were used as test materials in this study. The light extinction coefficient (ε) was found to correlate with the suspended dust concentration, and the ε values depended on the dust properties. Mass extinction coefficient (K) was obtained for cornstarch, saw dust and corn dust, from known suspended dust concentrations using image analysis. The mass extinction coefficient of the three sample materials tested in this study were in the range of 0.03–0.04. This method of using light extinction coefficient can be used for real-time sensing of suspended dust concentration in both open and confined spaces. 相似文献
999.
Declining worldwide phosphate rock reserves has driven a growing interest in exploration of alternative phosphate supplies. This study involved phosphorus recovery from swine wastewater through precipitation of struvite, a valuable slow-release fertiliser. The economic feasibility of this process is highly dependent on the cost of magnesium source. Two different magnesium sources were used for phosphorus recovery: pure magnesium chloride and nanofiltration(NF) saline water retentate. The paper f... 相似文献
1000.
Lu Zhao Evans Atoni Raphael Nyaruaba Yao Du Huaiyu Zhang Oscar Donde Doudou Huang Shuqi Xiao Nanjie Ren Teng Ma Zhu Shu Zhiming Yuan Lei Tong Han Xia 《环境科学学报(英文版)》2022,34(2):115-120
Wastewater-based epidemiology(WBE) has emerged as an effective environmental surveillance tool in monitoring fecal-oral pathogen infections within a community. Congruently, SARS-Co V-2, the etiologic agent of COVID-19, has been demonstrated to infect the gastrointestinal tissues, and be shed in feces. In the present study, SARS-Co V-2 RNA was concentrated from wastewater, sludge, surface water, ground water, sediment, and soil samples of municipal and hospital wastewater systems and related envi... 相似文献