全文获取类型
收费全文 | 445篇 |
免费 | 30篇 |
国内免费 | 214篇 |
专业分类
安全科学 | 36篇 |
废物处理 | 35篇 |
环保管理 | 38篇 |
综合类 | 269篇 |
基础理论 | 85篇 |
污染及防治 | 159篇 |
评价与监测 | 25篇 |
社会与环境 | 18篇 |
灾害及防治 | 24篇 |
出版年
2023年 | 15篇 |
2022年 | 17篇 |
2021年 | 20篇 |
2020年 | 23篇 |
2019年 | 20篇 |
2018年 | 25篇 |
2017年 | 25篇 |
2016年 | 26篇 |
2015年 | 42篇 |
2014年 | 37篇 |
2013年 | 54篇 |
2012年 | 50篇 |
2011年 | 38篇 |
2010年 | 33篇 |
2009年 | 29篇 |
2008年 | 26篇 |
2007年 | 39篇 |
2006年 | 17篇 |
2005年 | 16篇 |
2004年 | 10篇 |
2003年 | 13篇 |
2002年 | 20篇 |
2001年 | 8篇 |
2000年 | 10篇 |
1999年 | 17篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1996年 | 8篇 |
1995年 | 10篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1992年 | 7篇 |
1991年 | 1篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
排序方式: 共有689条查询结果,搜索用时 444 毫秒
491.
492.
To investigate short-term effects of ambient ozone exposure on mortality in Chinese cities, we conducted a meta-analysis of 10 effect estimates of 5 short-term studies, which reported associations between ambient ozone and mortality in Chinese mainland cities. And we estimated pooled effects by non-accidental mortality, cardiovascular mortality, and respiratory mortality. Combined estimates and their 95%CI were tested by RevMan 5, and Funnel plots were used for the bias analysis. For a 10 μg m−3 increase of maximum 8-h average concentration of ozone, the percent change for non-accidental mortality, cardiovascular mortality, and respiratory mortality were 0.42 (95%CI, 0.32–0.52%), 0.44% (95%CI, 0.17–0.70%) and 0.50% (95%CI, 0.22–0.77%), respectively. Compared with pooled estimates from other meta-analyses on ambient ozone-associated mortality, our pooled estimate for non-accidental mortality was slightly higher than previous ones and pooled estimate for cardiovascular mortality was consistent with others. However, we observed significantly positive association between ambient ozone and respiratory mortality, which were generally nonsignificant in earlier studies. By combining estimates from published evidence, a small but substantial association between ambient ozone level and mortality was observed in Mainland China. 相似文献
493.
Chi Z Lu W Mou Z Wang H Long Y Duan Z 《Journal of the Air & Waste Management Association (1995)》2012,62(3):278-286
A novel biocover with passive air diffusion system (PADS) was designed in this study. Its effect on landfill gas components in the macrocosms of simulated biocover systems was also investigated. The results show that O2 concentration increased in the whole profile of the macrocosms equipped with PADS. When simulated landfill gas (SLFG) flow rate was no more than 40 mL min(-1), the methane oxidation rate was 100%. The highest CH4 oxidation capacity reached to 31.34 mol m(-3) day(-1). Molecular microbiology analysis of the soil samples taken from the above macrocosm showed that the growth of type I methanotrophs was enhanced, attributable to enhanced air diffusion and distribution, whereas the microbial diversity and population density of type II methanotrophs were not so affected, as evidenced by the absence of any difference between the biocover equipped with PADS and that of the control. According to a phylogenic analysis, Methylobacter Methylosarcinafor type I, and Methylocystis, Methylosinus for type II, were the most prevalent species in the macrocosm with PADS. 相似文献
494.
改性硅藻土复合混凝剂处理深度采油废水 总被引:1,自引:0,他引:1
某油田深度采油废水中含有大量残油,粘度大、乳化程度高、油水分离困难,本实验采用改性硅藻土吸附和无机混凝剂混凝相结合以处理深度采油废水.结果表明,对于含油浓度为250~ 350 mg/L的石油废水,用强化吸附方法,吸附剂投加量为1.5 g/L,优化实验条件下除油率可达到75%;采用强化混凝的方法,PAC在投药量为200 mg/L的情况下除油率可达到87%;采用强化吸附-混凝联合处理的优化方法,投加0.7 g/L吸附剂+PAC 200 mg/L,除油率>95%,明显高于吸附和混凝单独处理效果,大大改善了出水水质. 相似文献
495.
Xianjun Xie Thomas M. Johnson Yanxin Wang Craig C. Lundstrom Andre Ellis Xiangli Wang Mengyu Duan 《Chemosphere》2013,90(6):1878-1884
Iron isotope compositions of various Fe pools in aquifer sediments were measured at a known As-contaminated site in the Datong Basin, China. The δ56Fe values of HCl-extracted poor-crystalline Fe(III) range widely from ?0.41‰ to 0.36‰. We interpret the low Fe(II)/FeExtractable ratios (<50%) and the negative correlation between Fe(II)/FeExtractable and δ56Fe values in HCl-extracted poor-crystalline Fe to be best explained by redox cycling of Fe induced by microbial Fe(III) reduction. However, the high Fe(II)/FeExtractable ratios (?70%) and positive correlation between Fe(II)/FeExtractable and δ56Fe values for HCl-extracted poor-crystalline Fe indicates production of sulfides (FeSs). The δ56Fe values of crystalline Fe(III) extracted by reductant appears to be comparatively small varying from ?0.01‰ to 0.24‰, which is consistent with the δ56Fe values for ferric oxides/hydroxides having undergone microbial Fe(III) reduction. The Fe isotope composition of various Fe pools shows the transformation between crystalline Fe(III) and poor-crystalline crystalline Fe(III) and the secondary Fe(II) phases has already occurred or is occurring in aquifer sediments. More importantly, there is a significant difference in the As concentrations in crystalline Fe(III) oxides/hydroxides and HCl-extracted Fe phases. The concentrations of As range from 1.6 to 29.9 mg kg?1 and from 0.6 to 3.0 mg kg?1, for crystalline Fe(III) and HCl-extracted Fe phases respectively. Accordingly, the transformation of Fe minerals induced by microbial Fe(III) reduction can contribute to the mobilization of As. This study is the first to examine the Fe isotope compositions in high As aquifer sediments; the results show that the Fe isotope would be an important tool in demonstrating the enrichment of As in groundwater. 相似文献
496.
497.
不同态二氧化钛处理模拟印染废水的研究 总被引:3,自引:2,他引:1
以普通载玻片为基底材料,负载态和悬浮态的纳米二氧化钛/普通二氧化钛被用于处理甲基红模拟印染废水,实验结果表明:纳米二氧化钛的脱色效果明显优于普通的二氧化钛,适当增加负载量和处理时间,负载态的处理效果与悬浮态相当。首次提出了由光源决定的纳米光催化活性激发理论,解释了不同光源辐照时脱色率变化曲线差异的问题,并发现纳米TiO2光催化氧化模拟印染废水的脱色反应,主要由吸附过程控制的表面反应机理;150 mL模拟印染废水中,加入3块纳米TiO2负载量1 mg/cm2的普通载玻片,3~5 mL ClO2或H2O2,紫外光照60 min后,脱色率达到99.2%。 相似文献
498.
景观富营养水体生态修复对浮游植物群落结构的影响 总被引:3,自引:2,他引:1
对以再生水为补给水源的北京稻香湖园林水系进行生态修复实验。通过对浮游植物群落和理化指标的分析,探讨浮游植物对生态修复的响应和修复效果。结果显示,生态修复实验实施后,TN、TP、COD和BOD5分别下降62.55%、66.42%、48.53%和40.95%,富营养程度明显降低;浮游植物密度和Chl-a含量分别下降86.1%和77.4%;Shan-non-Weaver物种多样性指数值从生态修复前低于2上升到2.74,且优势种群发生演替。相关分析表明:TP、PO4-P、pH与浮游植物密度呈极显著正相关(P(0.01);TN、NH4-N、NO2-N、COD和DO与浮游植物密度呈显著正相关(P(0.05);Chl-a含量与浮游植物密度呈极显著正相关(P(0.01)。浮游植物群落结构对城市富营养景观水系的生态修复措施表现出明显的响应。 相似文献
499.
以68台燃油锅炉(≤10.5 MW)NO_x排放实测数据为基础,通过统计分析方法,研究了NO_x的排放特征;通过对比分析,探讨了我国燃油锅炉NO_x排放控制与管理现状,讨论了进一步加强我国燃油锅炉NO_x排放管理控制的可能性与可行性,并提出了相应的管理控制建议。结果表明,NO_x平均排放浓度为318.2 mg/m~3,基于燃料消耗量的平均排放因子为4.4 kg/t,基于燃料发热量的平均排放因子为102.8 ng/J,基于燃料氮含量的平均排放因子为2.1 mg/mg;建议采取分阶段控制的方式,逐步提高NO_x排放限制,从而实现控源减排目标。 相似文献
500.
Zhigang Xue Jiming Hao Fahe Chai Ning Duan Yizhen Chen Jindan Li 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1816-1826
Abstract This paper analyzes the air quality impacts of coal-fired power plants in the northern passageway of the West-East Power Transmission Project in China. A three-layer Lagrangian model called ATMOS, was used to simulate the spatial distribution of incremental sulfur dioxide (SO2) and coarse particulate matter (PM10) concentrations under different emission control scenarios. In the year 2005, the emissions from planned power plants mainly affected the air quality of Shanxi, Shaanxi, the common boundary of Inner Mongolia and Shanxi, and the area around the boundary between Inner Mongolia and Ningxia. In these areas, the annually averaged incremental SO2 and PM10 concentrations exceed 2 and 2.5 µg/m3, respectively. The maximum increases of the annually averaged SO2 and PM10 concentrations are 8.3 and 7.2 µg/m3, respectively, which occur around Hancheng city, near the boundary of the Shaanxi and Shanxi provinces. After integrated control measures are considered, the maximum increases of annually averaged SO2 and PM10 concentrations fall to 4.9 and 4 µg/m3, respectively. In the year 2010, the areas affected by planned power plants are mainly North Shaanxi, North Ningxia, and Northwest Shanxi. The maximum increases of the annually averaged SO2 and PM10 concentrations are, respectively, 6.3 and 5.6 µg/m3, occurring in Northwest Shanxi, which decline to 4.4 and 4.1 µg/m3 after the control measures are implemented. The results showed that the proposed power plants mainly affect the air quality of the region where the power plants are built, with little impact on East China where the electricity will be used. The influences of planned power plants on air quality will be decreased greatly by implementing integrated control measures. 相似文献