全文获取类型
收费全文 | 3414篇 |
免费 | 176篇 |
国内免费 | 1016篇 |
专业分类
安全科学 | 212篇 |
废物处理 | 203篇 |
环保管理 | 293篇 |
综合类 | 1776篇 |
基础理论 | 594篇 |
环境理论 | 1篇 |
污染及防治 | 1123篇 |
评价与监测 | 162篇 |
社会与环境 | 106篇 |
灾害及防治 | 136篇 |
出版年
2024年 | 2篇 |
2023年 | 57篇 |
2022年 | 155篇 |
2021年 | 148篇 |
2020年 | 113篇 |
2019年 | 106篇 |
2018年 | 124篇 |
2017年 | 155篇 |
2016年 | 170篇 |
2015年 | 184篇 |
2014年 | 287篇 |
2013年 | 342篇 |
2012年 | 298篇 |
2011年 | 306篇 |
2010年 | 245篇 |
2009年 | 228篇 |
2008年 | 232篇 |
2007年 | 205篇 |
2006年 | 212篇 |
2005年 | 144篇 |
2004年 | 112篇 |
2003年 | 114篇 |
2002年 | 97篇 |
2001年 | 75篇 |
2000年 | 65篇 |
1999年 | 70篇 |
1998年 | 59篇 |
1997年 | 63篇 |
1996年 | 38篇 |
1995年 | 44篇 |
1994年 | 31篇 |
1993年 | 21篇 |
1992年 | 24篇 |
1991年 | 18篇 |
1990年 | 20篇 |
1989年 | 14篇 |
1988年 | 7篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1958年 | 2篇 |
1947年 | 1篇 |
1921年 | 1篇 |
1920年 | 1篇 |
1918年 | 1篇 |
排序方式: 共有4606条查询结果,搜索用时 15 毫秒
981.
多相催化-臭氧氧化法处理模拟有机磷农药废水 总被引:12,自引:0,他引:12
实验通过臭氧氧化法来降解模拟废水中的有机磷农药,将其转化为无害物质,并试验研究了在废水中加入2种自制的催化剂对降解结果的影响。采用气相色谱法测定水中有机磷农药的量。结果表明,只用臭氧处理的情况下1周后有机磷的去除率为78.03%;在催化剂A存在下,去除率可达93.85%;在催化剂B存在下,去除率可达为88.35%。结果表明,臭氧氧化法对此类污水:具有较好的降解作用,尤其在有催化剂存在的情况下处理效果更好,在室温和中性介质中均属于一级反应。 相似文献
982.
研究提出了用磷酸钕(NdPO4)作为共沉淀捕集剂分离富集环境水样中的痕量Pb2 ,用火焰原子吸收光谱(FAAS)测定的方法.共沉淀受pH、NdCl3和H3PO4溶液用量的影响.结果显示,在溶液pH为3.2时,20 mL水样中加入5 mg/L NdCl3 2 mL、0.5 mol/L H3PO4 3 mL条件下,铅的加标回收率为96.6%~104.2%,方法的检测限为5.7×10-3 mg/L,水体中常见碱金属、碱土金属离子及阴离子在一定范围内不影响测定. 相似文献
983.
984.
985.
986.
Tu C Ma LQ Zhang W Cai Y Harris WG 《Environmental pollution (Barking, Essex : 1987)》2003,124(2):223-230
Arsenic speciation is important not only for understanding the mechanisms of arsenic accumulation and detoxification by hyperaccumulators, but also for designing disposal options of arsenic-rich biomass. The primary objective of this research was to understand the speciation and leachability of arsenic in the fronds of Chinese brake (Pteris vittata L.), an arsenic hyperaccumulator, with an emphasis on the implications for arsenic-rich biomass disposal. Chinese brake was grown for 18 weeks in a soil spiked with 50 mg As kg(-1) as arsenate (AsO4(3-)), arsenite (AsO3(3-)), dimethylarsinic acid (DMA), or methylarsonic acid (MMA). Plant samples were extracted with methanol/water (1:1) and arsenic speciation was performed using high performance liquid chromatography coupled with atomic fluorescence spectrometry. The impacts of air-drying on arsenic species and leachability in the fronds were examined in the laboratory. After 18 weeks, water-soluble arsenic in soil was mainly present as arsenate with little detectable organic species or arsenite regardless of arsenic species added to the soil. However, arsenic in the fronds was primarily present as inorganic arsenite with an average of 94%. Arsenite re-oxidation occurred in the old fronds and the excised dried tissues. Arsenic species in the fronds were slightly influenced by arsenic forms added to the soil. Air-drying of the fronds resulted in leaching of substantial amounts of arsenic. These findings can be of significance when looking at disposal options of arsenic-rich biomass from the point of view of secondary contamination. 相似文献
987.
Ma HW 《Chemosphere》2002,48(10):1035-1040
The objectives of this study were to assess site-specific carcinogenic risk of incinerator-emitted dioxins in a manner reflecting pollutant transfer across multimedia and multi-pathways. The study used site-specific environmental and exposure information and combined the Monte Carlo method with multimedia modeling to produce probability distributions of risk estimates. The risk estimates were further categorized by contaminated environmental media and exposure pathways that are experienced by human receptors in order to pinpoint significant sources of risk. Rank correlation coefficients were also calculated along with the Monte Carlo sampling to identify key factors that influenced estimation of risk. The results showed that ingestion accounted for more than 90% of the total risk and that risk control on ingestion of eggs, aboveground vegetables, and poultry should receive priority. It was also found that variation of parameters with variability accounted for around 35% of the total risk variance, while uncertainty contributed to the remaining 65%. Intake rates of aboveground vegetables, eggs, and poultry were the key parameters with the largest contribution to variance. In addition, sufficient sampling and analysis of dioxin contents in eggs, aboveground vegetables, poultry, soil, and fruit should be performed to improve risk estimation because the variation in concentrations in these media accounted for the largest overall risk variance. Finally, focus should be placed on reduction of uncertainty associated with the risk estimation through ingestion of aboveground vegetables, eggs, poultry, fruit, and soil because the risk estimates associated with these exposure pathways had the largest variance. 相似文献
988.
Báez AP Torres Mdel C García RM Padilla HG 《Environmental science and pollution research international》2002,9(4):230-233
A great number of studies on the ambient levels of formaldehyde and other carbonyls in the urban rural and maritime atmospheres have been published because of their chemical and toxicological characteristics, and adverse health effects. Due to their toxicological effects, it was considered necessary to measure these compounds at different sites in the metropolitan area of Mexico City, and to calculate the total rate of photolytic constants and the photolytic lifetime of formaldehyde and acetaldehyde. Four sites were chosen. Sampling was carried out at different seasons and atmospheric conditions. The results indicated that formaldehyde was the most abundant carbonyl, followed by acetone and acetaldehyde. Data sets obtained from the 4 sites were chosen to calculate the total rate of photolysis and the photolytic lifetime for formaldehyde and acetaldehyde. Maximum photolytic rate values were obtained at the maximum actinic fluxes, as was to be expected. 相似文献
989.
990.
人工快速渗滤系统对污染物的去除机制 总被引:9,自引:0,他引:9
人工快速渗滤系统(CRI)是在传统的污水快速渗滤处理系统(RI)的基础上发展起来的一种新型的污水土地处理技术.通过对CRI的模拟,揭示了非生物机制与生物机制对有机物、营养元素的降解机制.结果表明,CRI对污水中污染物的去除是在非生物机制与生物机制协同作用下完成的.对污水中的有机物和氮的降解以生物机制为主、非生物机制为辅;对磷的降解则以非生物机制为主、生物机制为辅.生物机制对有机物、氮的去除占70%以上,非生物机制对磷的去除占61.9%.系统中氮转化以硝化效果为主,反硝化效果较弱. 相似文献