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111.
112.
上推流厌氧反应器连续干发酵猪粪产沼气试验研究 总被引:9,自引:0,他引:9
为解决猪粪连续干发酵存在的氨抑制和出料难等难题,在温度(25±2)℃、有机负荷为干物质(TS)4.44 g.(L.d)-1的条件下,采用上推流式厌氧反应器(UPAR)对猪粪进行连续干式发酵试验,研究了猪粪干发酵过程的产气情况、氨抑制现象和出料流动性,并考察了上推流厌氧反应器进行猪粪干发酵的可行性.试验采用4种不同TS质量分数(20%、25%、30%、35%)的猪粪作为原料,经160 d的运行.结果表明,进料TS质量分数对发酵过程有很大的影响,4种不同进料TS质量分数稳定的池容产气率分别为2.40、1.73、0.89、0.62 L.(L.d)-1,进料TS质量分数为20%、25%和30%的产气效率明显优于进料TS=35%的产气效率.随着进料TS质量分数从20%增加到35%,氨氮质量浓度>2 300 mg.L-1会出现明显的产气抑制.在进料TS=35%时,氨氮质量浓度能达到3 800 mg.L-1,产气速率相对于进料TS=20%递减74.1%.当进料TS达到35%、出料TS质量分数达到17.1%、流速<0.002 m.s-1时,UPAR不能顺利出料. 相似文献
113.
Yen-Hsun Chuang Winn-Jung Huang Kieu Lan Phuong Nguyen Wei-Yea Chen Ruey-Fang Yu 《Environmental Forensics》2019,20(1):77-91
Groundwater quality in coastal area has been an issue of interest because of excessive groundwater extraction for human use, for example, industrialization, irrigation, which can lead to saltwater intrusion. The study develops an integrated data analysis procedure based on multivariate statistics principal component analysis (PCA), hierarchical cluster analysis (HCA) and redundancy analysis (RDA), to determine the effects of key environmental conditions on the formulation of groundwater pollutants. This proposed method was demonstrated by analyzing groundwater quality monitoring data collected between 2011 and 2014 from four coastal industrial areas in Changhua county of Taiwan, namely Chuansing, Xianxi, Lukang and Fangyuan industrial parks. First, different environmental conditions in each industrial region were explored by PCA. The spatial hierarchy and spatial distribution of pollutant categories were then identified using HCA with the kriging method. Finally, the effect of environmental conditions on constitutive pollutants were identified with RDA. The three environmental patterns identified from the analytical results in Chuansing, Lukang and Xianxi were the salination factor (including conductivity and general hardness (GH)), water level and redox condition (including dissolved oxygen and oxidation–reduction potential). Fangyuan industrial park had only two patterns, namely salination (including conductivity and GH) and oxygen content (including DO and depth). The pollutant category indicated high concentrations of all pollutants in Chuansing and Fangyuan, and higher concentration of SO42?, TDS, Cl? in Xianxi, and of NH3-N, Mn, Fe and TOC in Lukang. According to RDA results, salination caused the high concentrations of NH3N, Cl?, TDS in Chuansing, and of Cl?, TDS and SO42? in Xianxi and Lukang. Additionally, salination caused high concentrations of Fe in both Lukang and Fangyuan industrial parks in combination with those three pollutants. The redox condition was linked to high content of NO3? in Chuansing and Lukang, and of TOC in Xianxi. In Fangyuan industrial park, NO3? was also linked to high oxygen concentration. In summary, the combination of PCA, HCA and RDA enables the analysis of monitoring data to support policy decision-making. 相似文献
114.
The purpose of this study is to examine why both parties (industry and consumer market) have mutual interests in protecting the environment but they still are hesitant to act green. The study used two-stage sampling from consumer market to depict ideal green product characteristics and reliable toy companies, and visit these companies for the second sample collection to examine whether the organizational eco-innovation strategy with customer value has a positive effect on green product development. In other words, the customer's benefit is an important factor for new product development strategy for green toys. This research shows that the willingness to buy green toys increases if most people in society buy green toys. This represents that customers are environmentally conscious and care about protecting the environment, or buying green toys is the result of a new economic trend and childhood education. The willingness to buy green toys increases if customers think that green products implies an enhancement on new product development to toy manufacturers. Further, if manufacturers are able to manage the difficulty of cooperation with all parties in the supply chain and difficulties related to production, they are willing to adopt customers' perceived value on green toys for their new product development strategy. It is rare to find academic research discussing the perspectives of both consumers and manufacturers in the same study because the research topic is very broad and many conditions must be considered. This research aims to find the effect of consumer-perceived value and company eco-innovation on green product development. 相似文献
115.
It is quite rare to find biodegradation in rapid sand filtration for drinking water treatment. This might be due to frequent backwashes and low substrate levels. High chlorine concentrations may inhibit biofilm development, especially for plants with pre-chlorination. However, in tropical or subtropical regions, bioactivity on the sand surface may be quite significant due to high biofilm development—a result of year-round high temperature. The objective of this study is to explore the correlation between biodegradation and chlorine concentration in rapid sand filters, especially for the water treatment plants that practise pre-chlorination. In this study, haloacetic acid (HAA) biodegradation was found in conventional rapid sand filters practising pre-chlorination. Laboratory column studies and field investigations were conducted to explore the association between the biodegradation of HAAs and chlorine concentrations. The results showed that chlorine residual was an important factor that alters bioactivity development. A model based on filter influent and effluent chlorine was developed for determining threshold chlorine for biodegradation. From the model, a temperature independent chlorine concentration threshold (Clthreshold) for biodegradation was estimated at 0.46-0.5 mg L−1. The results imply that conventional filters with adequate control could be conducive to bioactivity, resulting in lower HAA concentrations. Optimizing biodegradable disinfection by-product removal in conventional rapid sand filter could be achieved with minor variation and a lower-than-Clthreshold influent chlorine concentration. Bacteria isolation was also carried out, successfully identifying several HAA degraders. These degraders are very commonly seen in drinking water systems and can be speculated as the main contributor of HAA loss. 相似文献
116.
A high-throughput screening method using selective pressurized liquid extraction (SPLE) and enzyme-linked immunosorbent assay (ELISA) for monitoring dioxins in sediment and soil is described. SPLE conditions were developed by extracting sediment or soil together with alumina, 10% AgNO3 in silica, and sulfuric acid impregnated silica (acid silica) using dichloromethane (DCM) as the solvent at 100 °C and 2000 psi. Post-extraction cleanups were not required for ELISA. Two reference sediments (National Institute of Standards and Technology SRM 1944 and Wellington Laboratories WMS01) were analyzed by the SPLE–ELISA method. The ELISA utilized a polyclonal antibody and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as the calibrant. Recoveries of ELISA-derived TCDD equivalents (EQ) relative to the expected gas chromatography/high resolution mass spectrometry (GC/HRMS) derived dioxin toxic equivalent (TEQ) values were 116 ± 11% for SRM 1944 and 102 ± 13% for WMS01. ELISA TCDD EQs were consistent with the dioxin TEQs as measured by GC/HRMS for 25 soil/sediment samples from seven different contaminated sites. The ELISA had an approximate method detection limit of 10 pg g−1 with a precision of 2.6–29% based on the relative percentage difference (%RPD) for duplicate samples. Estimated sample throughput for the SPLE–ELISA was three times or more than that of the GC/HRMS method employing PLE with a multi-column cleanup. 相似文献
117.
选取万元GDP能耗作为参考序列,将工业发展过程中的5种主要污染物作为比较序列,运用灰色关联分析方法定量研究了河南省18个城市的环境管制和不同污染物之间的灰色关联程度,并提出了一些富有针对性的政策建议:加强监管,切实查找固体废弃物的产生来源,努力提高废弃物综合利用水平。 相似文献
118.
An iron oxide solid sponge H2S adsorbent works by reacting H2S and turning ferric oxide into ferric sulfide. The ferric sulfide will be converted back into ferric oxide and elemental sulfur when contacting oxygen or air. This study investigates the leaching of elemental sulfur from the solid sponge using anhydrous liquid ammonia as solvent. The leaching treatment expectedly results in effective regeneration of the adsorbent, which is able to lead to a sulfur removal and recovery process suitable for handling the small and mid-sized sulfur production cases, i.e., those less than 10 ton/day sulfur. The leaching does not significantly impair the physical properties, including the adsorbent pellet strength. The adsorption–regeneration (or leaching) cycle could be repeated at least three times. The cumulative sulfur loading can achieve as high as 50% (w/w), three times greater than that in the one-time use. The wash-off in leaching and the spent adsorbent can be made into slurry that is to be injected into underground formations such as depleted oil wells. It is anticipated that this underground injection is safer and more efficient than acid gas injection. 相似文献
119.
Wenguo Wang Chuang Yang Xiaoyu Tang Xinjiao Gu Qili Zhu Ke Pan Qichun Hu Danwei Ma 《Environmental science and pollution research international》2014,21(24):14202-14210
Growing common duckweed Lemna minor L. in diluted livestock wastewater is an alternative option for pollutants removal and consequently the accumulated duckweed biomass can be used for bioenergy production. However, the biomass accumulation can be inhibited by high level of ammonium (NH4 +) in non-diluted livestock wastewater and the mechanism of ammonium inhibition is not fully understood. In this study, the effect of high concentration of NH4 + on L. minor biomass accumulation was investigated using NH4 + as sole source of nitrogen (N). NH4 +-induced toxicity symptoms were observed when L. minor was exposed to high concentrations of ammonium nitrogen (NH4 +-N) after a 7-day cultivation. L. minor exposed to the NH4 +-N concentration of 840 mg l?1 exhibited reduced relative growth rate, contents of carbon (C) and photosynthetic pigments, and C/N ratio. Ammonium irons were inhibitory to the synthesis of photosynthetic pigments and caused C/N imbalance in L. minor. These symptoms could further cause premature senescence of the fronds, and restrain their reproduction, growth and biomass accumulation. L. minor could grow at NH4 +-N concentrations of 7–84 mg l?1 and the optimal NH4 +-N concentration was 28 mg l?1. 相似文献
120.
Yi-Hsuan Chuang Gui-Bing Hong 《Journal of the Air & Waste Management Association (1995)》2014,64(6):738-742
In this study, polyvinyl alcohol (PVA) and titania (TiO2) Degussa P-25 were mixed to generate TiO2 nonwoven filters using electrospinning. The wires of titanium dioxide and the nonwoven binding titania nanofibers were formed using 14 kV voltage and a distance of 15 cm. A single-factor experimental method was used to investigate the effects of parameters such as initial concentration, retention time, and light source on acetone removal by nonwoven binding titania nanofibers. Furthermore, the effects of parameters such as gas pressure, particle size, initial concentration, and retention time on the removal of particulates were also assessed. The results showed that the degradation efficiency increased with decreasing initial concentrations and increasing retention time. The best operational conditions during this study for the removal of acetone using the TiO2 nonwoven filters were a retention time of 100 sec, initial acetone concentration of 250 ppm, and ultraviolet (UV) light source of 254 nm. Under those conditions, 99% acetone removal efficiency was obtained. In addition, 90% particulate matter removal efficiency was reached when the particulate size was greater than 200 nm and the reaction time was longer than 5 minutes. The prepared TiO2/nanofiber has good performance for volatile organic compounds (VOCs) and particulate removal at the same time.
Implications: In this study, polyvinyl alcohol (PVA) and titania (TiO2) Degussa P-25 were mixed to generate TiO2 nonwoven filters using electrospinning. The results showed that the optimum operating conditions for the removal of acetone using the TiO2 nonwoven filters were a retention time of 100 sec, initial acetone concentration of 250 ppm, and UV light source of 254 nm. Under those conditions, 99% acetone removal efficiency was obtained. 相似文献