全文获取类型
收费全文 | 736篇 |
免费 | 52篇 |
国内免费 | 185篇 |
专业分类
安全科学 | 83篇 |
废物处理 | 45篇 |
环保管理 | 55篇 |
综合类 | 363篇 |
基础理论 | 106篇 |
污染及防治 | 227篇 |
评价与监测 | 34篇 |
社会与环境 | 39篇 |
灾害及防治 | 21篇 |
出版年
2023年 | 16篇 |
2022年 | 52篇 |
2021年 | 39篇 |
2020年 | 36篇 |
2019年 | 25篇 |
2018年 | 31篇 |
2017年 | 37篇 |
2016年 | 42篇 |
2015年 | 49篇 |
2014年 | 43篇 |
2013年 | 62篇 |
2012年 | 69篇 |
2011年 | 64篇 |
2010年 | 47篇 |
2009年 | 47篇 |
2008年 | 45篇 |
2007年 | 47篇 |
2006年 | 30篇 |
2005年 | 21篇 |
2004年 | 23篇 |
2003年 | 18篇 |
2002年 | 25篇 |
2001年 | 25篇 |
2000年 | 7篇 |
1999年 | 10篇 |
1998年 | 13篇 |
1997年 | 10篇 |
1996年 | 8篇 |
1995年 | 6篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有973条查询结果,搜索用时 15 毫秒
951.
为研究黄土地层浅埋暗挖隧道松散围岩压力特征,根据既有隧道施工现场裂缝扩展情况,假定隧道开挖后的土体存在破裂区,取一半破裂区土体进行静力极限平衡分析,考虑静止土压力、侧向土压力、隧道尺寸和土层参数对半结构的影响,推导出适用于黄土地层浅埋暗挖隧道的围岩压力解析式,确定该公式下的隧道深浅埋划分界限,并结合工程实例分析隧道埋深、静止土压力系数和侧压力系数对围岩压力的影响。研究结果表明:随隧道埋深增大,围岩压力存在峰值,围岩压力曲线呈先增大后减小的趋势;围岩压力随静止土压力系数和侧压力系数的增大而减小,但静止土压力系数对围岩压力的影响较大;将新方法得到的围岩压力值分别与现场实测值和既有理论围岩压力值进行对比,计算的垂直、侧向围岩压力值均大于实测值,且新方法的计算误差相对较小。 相似文献
952.
Won-Seok Yang Jang-Soo Lee Se-Won Park Jae-Jun Kang Tanvir Alam Yong-Chil Seo 《Journal of Material Cycles and Waste Management》2016,18(3):509-516
To recycle polyurethane foam waste generated from electric appliance recycling centers for use as fuel in a gasification process, polyurethane solid refuse fuel fabricated as pellets was analyzed for the characteristics of elemental composition, proximate analysis, heating value, and thermo-gravimetric testing. It has a high heating value of 29.06 MJ/kg with a high content of combustibles, which could be feasibly used in any thermal process. However, the nitrogen content, of up to 7 %, was comparably higher than for other fuels such as coal, biomass, and refuse-derived fuel, and may result in the emission of nitrogenous pollutant gases of HCN and NH3. By conducting gasification experiments on polyurethane solid refuse fuel in a fixed-bed reactor, a syngas with a heating value of 9.76 kJ/m3 and high content of both H2 and CO were produced with good gasification efficiency; carbon conversion 54 %, and cold gas efficiency 60 %. The nitrogenous pollutant gases in syngas were measured at the concentrations of 160 ppm hydrogen cyanide and 40 ppm ammonia, which may have to be reduced using proper cleaning technologies prior to the commercialization of gasification technology for polyurethane waste. 相似文献
953.
氧化-混凝工艺处理碱性含砷废水的技术改造 总被引:1,自引:0,他引:1
针对某锑冶炼厂已有氧化-混凝法处理碱性含砷废水工艺中存在的药剂成本较高的问题,通过将氧化剂由双氧水改为次氯酸钠,将混凝剂由硫酸铁改为聚合硫酸铁,并采用二次混凝工艺,得出了废水处理效率和药剂成本的变化情况。结果表明,经技术改造后的工艺能在保证废水处理效率的前提下,使药剂成本有较大幅度的下降。 相似文献
954.
Jinhui Liang Peng Gao Benhang Li Longfei Kang Li Feng Qi Han Yongze Liu Liqiu Zhang 《Frontiers of Environmental Science & Engineering》2022,16(12):150
955.
Kim Na Kyong Kang Dong Hee Lee Wonoh Kang Hyun Wook 《Environmental Modeling and Assessment》2022,27(3):461-472
Environmental Modeling & Assessment - As the number of enclosed residential buildings increases to minimize energy consumption, research on indoor air quality is becoming more important.... 相似文献
956.
Chen Kang Liao Chenggang Li Ping Li Xingong Li Xianjun Zuo Yingfeng 《Journal of Polymers and the Environment》2022,30(6):2209-2221
Journal of Polymers and the Environment - Poor interfacial compatibility between wheat straw and polylactic acid (PLA) remains a problem that directly affects the overall performance of wheat... 相似文献
957.
Na Liu Dan Li Kang Li Liping Wang Ruiwei Xu Jiaming Zhang Bairen Yang 《环境科学学报(英文版)》2021,33(5):108-118
Biotrickling filters (BTFs) for hydrophobic chlorobenzene (CB) purification are limited by mass transfer and biodegradation. The CB mass transfer rate could be improved by 150 mg/L rhamnolipids. This study evaluated the combined use of Fe3+ and Zn2+ to enhance biodegradation in a BTF over 35 day. The effects of these trace elements were analysed under different inlet concentrations (250, 600, 900, and 1200 mg/L) and empty bed residence times (EBRTs; 60, 45, and 32 sec). Batch experiments showed that the promoting effects of Fe3+/Zn2+ on microbial growth and metabolism were highest for 3 mg/L Fe3+ and 2 mg/L Zn2+, followed by 2 mg/L Zn2+, and lowest at 3 mg/L Fe3+. Compared to BTF in the absence of Fe3+ and Zn2+, the average CB elimination capacity and removal efficiency in the presence of Fe3+ and Zn2+ increased from 61.54 to 65.79 g/(m3?hr) and from 80.93% to 89.37%, respectively, at an EBRT of 60 sec. The average removal efficiency at EBRTs of 60, 45, and 32 sec increased by 2.89%, 5.63%, and 11.61%, respectively. The chemical composition (proteins (PN), polysaccharides (PS)) and functional groups of the biofilm were analysed at 60, 81, and 95 day. Fe3+ and Zn2+ significantly enhanced PN and PS secretion, which may have promoted CB adsorption and biodegradation. High-throughput sequencing revealed the promoting effect of Fe3+ and Zn2+ on bacterial populations. The combination of Fe3+ and Zn2+ with rhamnolipids was an efficient method for improving CB biodegradation in BTFs. 相似文献
958.
为保证含夹层盐岩储气库长期注采过程的安全稳定,开展夹层几何特征对盐岩储气库注采运行稳定性影响的研究.通过FLAC3D开展数值模拟,研究单一夹层厚度、位置及夹层数量等几何特征对储气库围岩应力、变形的影响规律,并分析盐腔的稳定性和可用性对夹层几何参数的敏感性特征.结果 表明:随夹层厚度、数量的增加,盐腔围岩所受压应力增大,... 相似文献
959.
The Fenton's system is applied to the destruction of perchloroethylene (PCE) present as a dense non-aqueous phase liquid (DNAPL) in soil slurry systems; the initial concentration of PCE was 45 times higher than its aqueous solubility. Studies were conducted in two matrices: Ottawa sand and soil from Warsaw, IN. In Ottawa sand, a 60-62% decrease in PCE concentration was observed, and Cl(-) recovery was 47-58%, whereas in Warsaw soil, a 44-49% decrease in PCE concentration and a Cl(-) recovery of 40-42% were observed after the addition of 600 mM H(2)O(2) and 10 mM dissolved iron. Significantly enhanced destruction resulted during application of N-(2-hydroxyethyl) iminodiacetic acid (HEIDA) to Warsaw soil. For example, in the absence of HEIDA in Warsaw soil, 36% PCE loss and 33% Cl(-) release were observed at 600 mM H(2)O(2) and 5 mM Fe(III), while 74% PCE loss and 63% Cl(-) release were achieved at 600 mM H(2)O(2) and 5 mM Fe(III)-HEIDA. For both soils, the catalytic activities of Fe(II) and Fe(III) were nearly equivalent. These findings clearly demonstrate that system design can be optimized with regard to process variables in Fenton's treatment of DNAPL in soils. 相似文献
960.
在实验室条件下,研究了Shewanella oneidensis MR-1对磺胺甲噁唑(Sulfamethoxazole,SMX)的降解特性以及低分子有机酸强化Fe(Ⅲ)还原介导的S.oneidensis MR-1对SMX的降解.结果表明,S.oneidensis MR-1对不同浓度SMX的降解能力与体系中的有机酸和Fe(Ⅲ)密切相关.低浓度SMX对其生长影响不大,高浓度时细菌生长则受到抑制,进而抑制SMX的降解率.当低分子有机酸单独加入体系后,S.oneidensis MR-1对SMX的最大降解率为58.5%;Fe(Ⅲ)单独加入体系后,S.oneidensis MR-1对SMX的最大降解率为67.6%.此外,当柠檬酸和Fe(OH)3同时加入体系后,S.oneidensis MR-1对SMX生物降解和铁还原作用促进效果最显著,培养5 d后SMX降解率为90.3%.最后,采用液相色谱-质谱联用仪(LC-MS)对SMX的降解中间产物进行了分析,推测SMX的可能降解途径是由S-N键断裂引起的.本研究以期为地下水污染场地修复提供理论依据. 相似文献