全文获取类型
收费全文 | 412篇 |
免费 | 8篇 |
国内免费 | 19篇 |
专业分类
安全科学 | 31篇 |
废物处理 | 41篇 |
环保管理 | 34篇 |
综合类 | 42篇 |
基础理论 | 55篇 |
污染及防治 | 162篇 |
评价与监测 | 44篇 |
社会与环境 | 30篇 |
出版年
2023年 | 3篇 |
2022年 | 8篇 |
2021年 | 9篇 |
2020年 | 3篇 |
2019年 | 8篇 |
2018年 | 18篇 |
2017年 | 16篇 |
2016年 | 25篇 |
2015年 | 10篇 |
2014年 | 20篇 |
2013年 | 33篇 |
2012年 | 31篇 |
2011年 | 29篇 |
2010年 | 19篇 |
2009年 | 26篇 |
2008年 | 30篇 |
2007年 | 37篇 |
2006年 | 30篇 |
2005年 | 21篇 |
2004年 | 12篇 |
2003年 | 10篇 |
2002年 | 21篇 |
2001年 | 5篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1994年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有439条查询结果,搜索用时 437 毫秒
211.
The growing interest in the anaerobic ammonium oxidizing (AMX) process in treating high nitrogen containing wastewaters and a comprehensive study into the granulation mechanism of these bacteria under diverse environmental conditions over the years have been unequal. To this effect, the distinctive differences in saline adapted AMX (S_AMX) and non-saline adapted AMX (NS_AMX) granules are presented in this study. It was observed that substrate utilisation profiles, granule formation mechanism, and pace towards granulation differed marginally for the two adaptation conditions. The different microbial dominant aggregation types aided in splitting the 471 days operated lab-scale SBRs into three distinct phases. In both reactors, phase III (granules dominant phase) showed the highest average nitrogen removal efficiency of 87.9% ± 4.8% and 85.6% ± 3.6% for the S_AMX and NS_AMX processes, respectively. The extracellular polymeric substances (EPS) quantity and major composition determined its role either as a binding agent in granulation or a survival mechanism in saline adaptation. It was also observed that granules of the S_AMX reactor were mostly loosely and less condensed aggregates of smaller sub-units and flocs while those of the NS_AMX reactor were compact agglomerates. The ionic gradient in saline enrichment led to an increased activity of the Na+/K+ – ATPase, hence enriched granules produced higher cellular adenosine triphosphate molecules which finally improved the granules active biomass ratio by 32.96%. Microbial community showed that about three to four major known AMX species made up the granules consortia in both reactors. Proteins and expression of functional genes differed for these different species. 相似文献
212.
Torrefaction is thermo-chemical process which can improve solid fuel quality as well as grindability. In previous studies, torrefaction has been studied mainly for removal of moisture and for improving grindability. In this experiment, the characteristics of torrefied waste sawdust were studied especially for its energy yield. Hence, torrefaction was performed on varying reaction temperatures (200, 220, 240, 260, 280, 300 °C) and solid residence time (10, 30, 60 min). The results indicated that the yield of torrefaction decreases with increasing temperature and residence time. It was found that above 280 °C, the yield got remarkably decreased. The lowest yield was obtained at the residence time of 60 min. It was also noticed that the HHV of torrefied samples increases with increasing temperature. The highest HHV was found to be 26.09 MJ/kg which was obtained at 60 min and 300 °C. However, the highest energy yield was obtained to be 104.17 % which was noticed at 30 min and 260 °C. 相似文献
213.
Journal of Material Cycles and Waste Management - This study aims to promote and revitalise quality control by efficiently separating impurities from recycled fine aggregates and soil. To meet this... 相似文献
214.
Lee Hyun-Kyu Choi Jung-Weon Kim Jin-Hee Kim Cho-Rong Choi Sang-June 《Environmental science and pollution research international》2021,28(31):42014-42023
Environmental Science and Pollution Research - Composite beads consisting of Ca alginate mixed with zinc ferrocyanide (ZnFC) and Cyanex 272 were synthesized in order to selectively adsorb Cs+ and... 相似文献
215.
Ji Eun Lee Hang Seok Choi Yong Chil Seo 《Journal of Material Cycles and Waste Management》2014,16(4):665-676
For designing an efficient circulating fluidized bed reactor, understanding the complex hydrodynamic characteristics in the reactor is required. Hence, in the present study, the modeling and simulation of the circulating fluidized bed gasifier using plastic waste were carried out with Eulerian-Granular approach. Several cases were investigated as changing superficial gas velocities or sizes of plastic waste particle. Firstly, cases were examined with four different velocities when the particle diameter is 1 mm. At the gas velocity of 6 or 8 m/s, gas volume fraction is more than 95 % throughout the reactor and particle velocity has positive value overall. Therefore, a circulating fluidized bed seems to be formed in both cases. Comparing those two cases, better solid mixing can be expected considering the mass fraction and solid velocity at the superficial gas velocity of 6 m/s. Thus this case was further studied for the effect of particle size. As the diameters of plastic waste particle are 1 or 3 mm, it is considered that a circulating fluidized bed is formed. And plastic waste and sand particles are well mixed throughout the reactor. However, the particle diameter increases over 3 mm then, it is very hard to maintain circulating fluidization condition. 相似文献
216.
Ganga Ram Maharjan Youn Shik Park Nam Won Kim Dong Seok Shin Jae Wan Choi Geun Woo Hyun Ji-Hong Jeon Yong Sik Ok Kyoung Jae Lim 《Frontiers of Environmental Science & Engineering》2013,7(1):109-119
A study was undertaken for the prediction of runoff flow from 0.8 ha field-sized agricultural watershed in South Korea using Soil and Water Assessment Tool (SWAT) sub-daily. The SWAT model with sub-daily configuration predicted flow from the watershed within the range of acceptable accuracy. The SWAT sub-daily simulations were carried out for a total of 18 rainfall events, 9 each for calibration and validation. Overall trend and extent of matching simulated flow for the rainfall events in 2007-2008 with measured data during the calibration process were coefficient of determination (R 2) value of 0.88 and Nash and Sutcliffe Efficiency (E NS) value of 0.88. For validation, R 2 and E NS values were 0.9 and 0.84, respectively. Whereas R 2 and E NS values for simulation results using daily rainfall data were 0.79 and -0.01, respectively, that were observed to be out of acceptable limits for the model simulation. The importance of higher time resolution (hourly) precipitation records for flow simulation were evaluated by comparing R 2 and E NS with 15 min, 2 h, 6 h and 12 h precipitation data, which resulted in lower statistics with increases in time resolution of precipitation data. The SWAT sub-daily sensitivity analysis was performed with the consideration of hydraulic parameter and was found as in the rank order of CN2 (curve number), ESCO (soil evaporation compensation factor), GW_DELAY (ground water delay time), ALPHA_BF ( base flow alpha factor), GWQMN ( a threshold minimum depth of water in the shallow aquifer required for return flow to occur) , REVAPMN (minimum depth of water in shallow aquifer for re-evaporation to occur) , LAT_TIME (lateral flow travel time) respectively. These sensitive parameters were evaluated at 10% higher and lower values of the parameters, corresponding to 70.5% higher and 23.2% lower in simulated flow out from the SWAT model. From the results obtained in this study, hourly precipitation record for SWAT sub-daily with Green-Ampt infiltration method was proven to be efficient for runoff estimation at field sized watershed with higher accuracies that could be efficiently used to develop site-specific Best Management Practices (BMPs) considering rainfall intensity, rather than simply using daily rainfall data. 相似文献
217.
Y.-B. Yi J.-L. Lee Y.-H. Choi S.-M. Park C.-H. Chung 《Environmental Chemistry Letters》2012,10(1):13-19
We report for the first time the direct conversion of raw grape berry biomass to hydroxymethylfurfural (HMF) using ionic liquid
solvents with metal chloride catalysts. Exploiting raw plant biomass as a biorefinery feedstock is innovative for sustainable
chemical industry. The use of the raw biomass to synthesize compounds can indeed lead to less energy consumption and less
CO2 emissions. Using raw plant biomass skips pretreatment steps that are required to produce biomaterials such as carbohydrates
or cellulosic biomass. Here, grape berry biomass was used as a raw chemical feedstock for the production of hydroxymethylfurfural,
a key platform intermediate for syntheses of future renewable biofuels. We examined 3 ionic liquid solvents, 3 reaction temperatures,
5 chloride catalysts, and 5 concentrations of HCl. We found an increasing HMF yields depending on reaction conditions. 1-octyl-3-methylimidazolium
chloride was most effective for HMF synthesis. Addition of HCl or metal chlorides alone showed little improvement. The highest
HMF yield of about 100 mg HMF per mL of grape biomass extract was obtained using 0.3 M HCl, [OMIM]Cl, and CrCl2 at 100°C for 3 h. Our study provides a model system of sustainable production of valuable compounds from raw plant biomass. 相似文献
218.
The present study examines the effects of training and development on organizational innovation. We specifically suggest that the training and development investments of an organization affect its innovative performance by promoting various learning practices. We empirically tested our hypothesis by using time‐lagged, multi‐source data collected from 260 Korean companies that represent diverse industries. Our analysis showed that corporate expenditure for internal training predicts interpersonal and organizational learning practices, which, in turn, increase innovative performance. The data also revealed that the positive relationship between interpersonal and organizational learning practices and innovative performance is stronger within organizations that have stronger innovative climates. By contrast, investment in employee development through financial support for education outside an organization poses a significant negative effect on its innovative performance and no significant effect on learning practices. The present study provides a plausible explanation for a mechanism through which the investment of an organization in employees enhances its innovative performance. Copyright © 2013 The Authors. Journal of Organizational Behavior published by John Wiley & Sons, Ltd. 相似文献
219.
Sanath KONDAVEETI Kwang Soon CHO Ramesh KAKARLA Booki MIN 《Frontiers of Environmental Science & Engineering》2014,8(5):784-791
Renewable algae biomass, Scenedesmus obliquus, was used as substrate for generating electricity in two chamber microbial fuel cells (MFCs). From polarization test, maximum power density with pretreated algal biomass was 102mW·m^2 (951mW·m^3) at current generation of 276mA·m^-2. The individual electrode potential as a function of current generation suggested that anodic oxidation process of algae substrate had limitation for high current generation in MFC. Total chemical oxygen demand (TCOD) reduction of 74% was obtained when initial TCOD concentration was 534mg · L^-1 for 150 h of operation. The main organic compounds of algae oriented biomass were lactate and acetate, which were mainly used for electricity generation. Other byproducts such as propionate and butyrate were formed at a negligible amount. Electrochemical Impedance Spectroscopy (EIS) analysis pinpointed the charge transfer resistance (112Ω ) of anode electrode, and the exchange current density of anode electrode was 1214 nA·cm^-2. 相似文献
220.
Muhammad Kashif Shahid Yunjung Kim Young-Gyun Choi 《Frontiers of Environmental Science & Engineering》2019,13(5):71