全文获取类型
收费全文 | 1236篇 |
免费 | 74篇 |
国内免费 | 459篇 |
专业分类
安全科学 | 90篇 |
废物处理 | 55篇 |
环保管理 | 107篇 |
综合类 | 736篇 |
基础理论 | 201篇 |
污染及防治 | 411篇 |
评价与监测 | 78篇 |
社会与环境 | 43篇 |
灾害及防治 | 48篇 |
出版年
2024年 | 1篇 |
2023年 | 17篇 |
2022年 | 42篇 |
2021年 | 38篇 |
2020年 | 33篇 |
2019年 | 33篇 |
2018年 | 43篇 |
2017年 | 58篇 |
2016年 | 58篇 |
2015年 | 83篇 |
2014年 | 108篇 |
2013年 | 121篇 |
2012年 | 105篇 |
2011年 | 105篇 |
2010年 | 104篇 |
2009年 | 67篇 |
2008年 | 71篇 |
2007年 | 69篇 |
2006年 | 73篇 |
2005年 | 42篇 |
2004年 | 46篇 |
2003年 | 44篇 |
2002年 | 53篇 |
2001年 | 53篇 |
2000年 | 49篇 |
1999年 | 46篇 |
1998年 | 48篇 |
1997年 | 44篇 |
1996年 | 25篇 |
1995年 | 23篇 |
1994年 | 22篇 |
1993年 | 14篇 |
1992年 | 13篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1981年 | 1篇 |
排序方式: 共有1769条查询结果,搜索用时 787 毫秒
501.
Primitive e-waste dismantling activities have been of increasing concern due to serious environmental and human health problems, and therefore authorities in China have strengthened the regulations on illegal e-waste recycling activities. In this work, we used rice hull as a passive sampler and investigated temporal trends of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) in areas near e-waste recycling sites after the stricter regulations. Furthermore, the distribution patterns and composition profiles of these contaminants were also discussed. The average concentrations of the three groups of persistent organic pollutants (POPs) in rice hulls have markedly decreased during the period of 2005-2009. Specifically, from 12.9 (average value in 2005) to 0.37 pg WHO-TEQ/g (dry weight, dw) (in 2009) for PCDD/Fs, 47.6 (2005) to 7.10 ng g−1 dw (2009) for PCBs, and 2.51 (2005) to 0.89 ng g−1, dw (2009) for PBDEs. The significant decrease of combustion markers 2,3,4,7,8-PeCDF, 1,2,3,6,7,8HxCDF and PCB126, and the PCDD/PCDF ratio from 1:9 (2005) to 7:3 (2009) is likely a result of stricter regulations on open combustion activities. This study suggests that stricter control measures, strengthened laws and regulations and more environmental friendly techniques could be effective measures in reducing the release and formation of related POPs in typical e-waste dismantling sites, and these measures could further improve the quality of the environment and health of the local inhabitants. 相似文献
502.
The behaviors and fate of polycyclic aromatic hydrocarbons (PAHs) in a coking wastewater treatment plant 总被引:4,自引:0,他引:4
The occurrence, behaviors and fate of 18 PAHs were investigated in a coking wastewater treatment plant in Songshan coking plant, located in Shaoguan, Guangdong Province of China. It was found that the target compounds occurred widely in raw coking wastewater, treated effluent, sludge and gas samples. In raw coking wastewater, high molecular weight (MW) PAHs were the dominant compounds, while 3-6 ring PAHs predominated in the final effluent. The dominant compounds in gas samples were phenathrene, fluoranthene and pyrene, while they were fluoranthene, pyrene, chrysene and benzo[k]fluoranthene for sludge. The process achieved over 97% removal for all the PAHs, 47-92% of eliminations of these target compounds in liquid phase were achieved in biological stage. Different behaviors of PAHs were observed in the primary tank, anaerobic tank, aerobic tank, hydrolytic tank and coagulation tank units, while heavier and lower ones were mainly removed in anaerobic tank and aerobic tanks, respectively. Regarding the fate of PAHs, calculated fractions of mass losses for low MW PAHs due to transformation and adsorption to sludge accounted for 15-50% and 24-49%, respectively, while the rest was less than 1%. For high MW PAHs, the mass losses were mainly due to adsorption to sludge and separation with tar (contributing 56-76% and 22-39%, respectively), and the removal through transformation was less. 相似文献
503.
An T Zhang D Li G Mai B Fu J 《Environmental pollution (Barking, Essex : 1987)》2011,159(12):3529-3535
Gas samples and total suspended particle during work and off work time were investigated on-site and off-site electronic waste dismantling workshop (I- and O-EWDW), then compared with plastic recycling workshop (PRW) and waste incineration plant (WIP). TSP concentrations and total PBDE were 0.36-2.21 mg/m3 and 27-2975 ng/m3 at different workshops, respectively. BDE-47, -99, and -209 were major ∑PBDE congeners at I-EWDW and WIP, while BDE-209 was only dominant congener in PRW and control sites during work time and all sites during off work time. The gas-particle partitioning result was well correlated with the subcooled liquid vapor pressure for all samples, except for WIP and I-EDWD, at park during work time, and residential area during off work time. The predicted urban curve fitted well with measured φ values at O-DEWD during work time, whereas it was slightly overestimated or underestimated for others. Exposure assessment revealed the highest exposure site was I-EDWD. 相似文献
504.
One major challenge faced by Beijing is dealing with the enormous amount of municipal solid waste (MSW) generated, which contains a high percentage of food waste. Source separation is considered an effective means of reducing waste and enhancing recycling. However, few studies have focused on quantification of the mechanism of source separation activity. Therefore, this study was conducted to establish a mathematical model of source separation activity (MSSA) that correlates the source separation ratio with the following parameters: separation facilities, awareness, separation transportation, participation atmosphere, environmental profit, sense of honor, and economic profit. The MSSA consisted of two equations, one related to the behavior generation stage and one related to the behavior stability stage. The source separation ratios of the residential community, office building, and primary and middle school were calculated using the MSSA. Data for analysis were obtained from a 1-yr investigation and a questionnaire conducted at 128 MSW clusters around Beijing. The results revealed that office buildings had an initial separation ratio of 80% and a stable separation ratio of 65.86%, whereas residential communities and primary and middle schools did not have a stable separation ratio. The MSSA curve took on two shapes. In addition, internal motivations and the separation transportation ratio were found to be key parameters of the MSSA. This model can be utilized for other cities and countries. 相似文献
505.
506.
507.
508.
Yunhee Kim Joshua S. Fu Terry L. Miller 《Atmospheric environment (Oxford, England : 1994)》2010,44(4):523-532
Meteorological variables such as temperature, wind speed, wind directions, and Planetary Boundary Layer (PBL) heights have critical implications for air quality simulations. Sensitivity simulations with five different PBL schemes associated with three different Land Surface Models (LSMs) were conducted to examine the impact of meteorological variables on the predicted ozone concentrations using the Community Multiscale Air Quality (CMAQ) version 4.5 with local perspective. Additionally, the nudging analysis for winds was adopted with three different coefficients to improve the wind fields in the complex terrain at 4-km grid resolution. The simulations focus on complex terrain having valley and mountain areas at 4-km grid resolution. The ETA M–Y (Mellor–Yamada) and G–S (Gayno–Seaman) PBL schemes are identified as favorite options and promote O3 formation causing the higher temperature, slower winds, and lower mixing height among sensitivity simulations in the area of study. It is found that PX (Pleim–Xiu) simulation does not always give optimal meteorological model performance. We also note that the PBL scheme plays a more important role in predicting daily maximum 8-h O3 than land surface models. The results of nudging analysis for winds with three different increased coefficients' values (2.5, 4.5, and 6.0 × 10?4 s?1) over seven sensitivity simulations show that the meteorological model performance was enhanced due to improved wind fields, indicating the FDDA nudging analysis can improve model performance considerably at 4-km grid resolution. Specifically, the sensitivity simulations with the coefficient value (6.0 × 10?4) yielded more substantial improvements than with the other values (2.5 and 4.5 × 10?4). Hence, choosing the nudging coefficient of 6.0 × 10?4 s?1 for winds in MM5 may be the best choice to improve wind fields as an input, as well as, better model performance of CMAQ in the complex terrain area. As a result, a finer grid resolution is necessary to evaluate and access of CMAQ results for giving a detailed representation of meteorological and chemical processes in the regulatory modeling. A recommendation of optimal scheme options for simulating meteorological variables in the complex terrain area is made. 相似文献
509.
研究公众自然灾害知觉中的不安全因素,有助于开展有针对性的减灾宣教活动、构建社会预防文化。通过问卷方式,调查了北京5所高校大学生的自然灾害知觉现状及特征。统计分析显示,大学生自然灾害知觉中存在不安全心理特性,主要表现在:对自身灾害知识和经验存在过高估计的乐观偏差;在灾害预期中表现出悲观的心理噪声效应;面对自然灾害多数出现消极情绪,其应急行为倾向呈负距平状态;防灾减灾过程中对政府行为依赖性、服从性高。在此基础上,提出了通过普及正确防灾知识、完善心理防御机制、强化能动意识等重塑大学生灾害知觉、调适灾害行为的建议。 相似文献
510.