全文获取类型
收费全文 | 147篇 |
免费 | 9篇 |
国内免费 | 52篇 |
专业分类
安全科学 | 11篇 |
废物处理 | 7篇 |
环保管理 | 9篇 |
综合类 | 95篇 |
基础理论 | 30篇 |
污染及防治 | 45篇 |
评价与监测 | 5篇 |
灾害及防治 | 6篇 |
出版年
2023年 | 3篇 |
2022年 | 7篇 |
2021年 | 9篇 |
2020年 | 9篇 |
2019年 | 3篇 |
2018年 | 5篇 |
2017年 | 5篇 |
2016年 | 6篇 |
2015年 | 12篇 |
2014年 | 10篇 |
2013年 | 13篇 |
2012年 | 12篇 |
2011年 | 11篇 |
2010年 | 10篇 |
2009年 | 10篇 |
2008年 | 11篇 |
2007年 | 9篇 |
2006年 | 14篇 |
2005年 | 7篇 |
2004年 | 1篇 |
2003年 | 3篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 6篇 |
1999年 | 7篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 6篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1992年 | 4篇 |
1989年 | 1篇 |
排序方式: 共有208条查询结果,搜索用时 738 毫秒
51.
Rui Han Shuxiao Wang Wenhai Shen Jiandong Wang Kang Wu Zhihua Ren Mingnong Feng 《环境科学学报(英文版)》2016,28(8):134-146
The purpose of this study is to analyze the climatic characteristics and long-term spatial and temporal variations of haze occurrence in China. The impact factors of haze trends are also discussed. Meteorological data from 1961 to 2012 and daily PM10 concentrations from 2003 to 2012 were employed in this study. The results indicate that the annual-average hazy days at all stations have been increasing rapidly from 4 days in 1961 to 18 days in 2012. The maximum number of haze days occur in winter (41.1%) while the minimum occur in summer (10.4%). During 1961-2012, the high occurrence areas of haze shifted from central to south and east regions of China. The Beijing-Tianjin-Hebei (Jing-Jin-Ji) region, Shanxi, Shaanxi, and Henan Province are the high occurrence areas for haze, while the Yangtze River Delta (YRD) and the Pearl River Delta (PRD) have become regions with high haze occurrences in the last 25 years. Temperature and pressure are positively correlated with the number of haze days. However, wind, relative humidity, precipitation, and sunshine duration are negatively correlated with the number of haze days. The key meteorological factors affecting the formation and dissipation of haze vary for high and low altitudes, and are closely related to anthropogenic activities. In recent years, anthropogenic activities have played a more important role in haze occurrences compared with meteorological factors. 相似文献
52.
Xinbo Zhu Chenghang Zheng Xiang Gao Xu Shen Zhihua Wang Zhongyang Luo Kefa Cen 《环境科学学报(英文版)》2014,26(11):2249-2256
Non-thermal plasma technology has been regarded as a promising alternative technology for NOx removal. The understanding of NO2 reduction characteristics is extremely important since NO2 reduction could lower the total NO oxidation rate in the plasma atmosphere. In this study, NO2 reduction was experimentally investigated using a non-thermal plasma reactor driven by a pulsed power supply for different simulated gas compositions and operating parameters. The NO2 reduction was promoted by increasing the specific energy density (SED), and the highest conversion rates were 33.7%, 42.1% and 25.7% for Ar, N2/Ar and O2/Ar, respectively. For a given SED, the NO2 conversion rate had the order N2/Ar 〉 Ar 〉 02/Ar. The highest energy yield of 3.31 g/kWh was obtained in N2/Ar plasma and decreased with increasing SED; the same trends were also found in the other two gas compositions. The conversion rate decreased with increasing initial NO2 concentration. Furthermore, the presence of N2 or O2 led to different reaction pathways for NO2 conversion due to the formation of different dominating reactive radicals. 相似文献
53.
Leather processing has been an important light industry in China, which has contributed a lot to economy. The recent environmental challenges caused tremendous pressure to leather manufacture. The conventional beam house processes employ a wide range of chemicals which result in more than 60% of the total pollution in leather processing (mainly based on COD, BOD, TS, SS, NH3–N). In this study, cleaner beam house processes were tested on cattle sofa leather to provide a clean environment. A control experiment was run parallel using conventional beam house processes. The results show that the de-hairing is complete through pelt histological microstructure, the extent of opening up of fibre bundles is very good, which is substantiated through chrome distribution analysis, scanning electron microscopic pictures of wet blue leathers and the analysis of contents of total proteins, polysaccharide and hydroxyproline in composite liquor, and the performance of the leathers is shown to be satisfied with the quality standard of sofa leather. The results from composite water analysis show that the cleaner processes enjoy in the reduction of emission water, chemical oxygen demand, total solids and ammonia-nitrogen loads by 46%, 93%, 58% and 54%, respectively, compared to the conventional processes. The total dry sludge from the clean processes is almost eliminated, and the composite cost is decreased by 10%. 相似文献
54.
55.
根据对云南曲靖—昭通断裂带北段的大毛滩断裂上多次野外地震地质调查和探槽揭露,发现有较多的古地震遗迹,如地震断层陡坎、崩塌体、地震沟槽、堰塞塘和断裂崩积楔等。主要分布于大毛滩断裂的纸厂坝、苏田坝、大毛滩和六马场地区和木杆河断裂的手扒岩、马家坪一带。 该区晚更新世晚期至全新世以前,曾发生过四次古地震事件,地震时间间隔为 4000—7000 年;距今5000--10000 年,发生过两次古地震,时间间隔为1500—2000 年,从5000 年至有历史记载的公元 1216马湖地震,古地震的时间间隔可能是 1000—1600年(不计田坝、丁木、李子湾事件);自公元 1216 年到现今的 782 年间,共发生了四次强烈地震,平均时间间隔为 195年,但从1844年以后,地震的时间间隔为 73—57年。可以看出自公元1216年以来,该区的地震时间间隔在大大地缩短。 相似文献
56.
57.
为有效预警原油储备区储罐气体泄漏,制定气体探测器布置优化方案,以某大型原油站库为例,基于CFD法和FLACS软件模拟原油泄漏及可燃蒸汽云溢散分布,通过分析蒸汽云扩散规律,实现全方位气体探测器优化布置.结果表明:原油储罐区探测器分别布置在区块21-2、6-1、31-1、40-2,且每个罐组总计布置16处;优化设置方案可满... 相似文献
58.
59.
含盐量对好氧颗粒污泥稳定性及微生物组成的影响 总被引:2,自引:1,他引:1
研究了不同含盐量(以NaCl质量分数计)对好氧颗粒污泥稳定性及微生物组成的影响.扫描电镜观察发现,高含盐量(5.0%)与低含盐量(1.0%和2.5%)下好氧颗粒污泥微生物的组成有较大的差异.低含盐量下好氧颗粒污泥的微生物以细菌(杆菌和球菌)为主;高含盐量下易出现大量的丝状菌,并形成白色和黑色的丝状颗粒污泥,而且丝状颗粒污泥在短期内(1个月左右)仍具有较好的沉降性能和密实性.但这些丝状颗粒污泥在实验后期易变得大而疏松,最终导致反应器运行失败.因此,维持丝状颗粒污泥的密实成长并抑制其发散成长成为控制好氧颗粒污泥稳定运行的关键,尚需进一步研究. 相似文献
60.
社会经济的发展和生活水平的提高使得汽车保有量逐年增加,服役后报废汽车产生的废旧蓄电池也快速上升,报废的蓄电池给环境带来巨大压力.废旧电池外壳是聚丙烯,如何循环利用成为亟待解决问题.采用高抗冲共聚聚丙烯对其进行增韧改性,结果表明:当添加20%共聚聚丙烯后,缺口冲击强度提升39.2%,熔体流动速率降低了48.3%,在150... 相似文献