全文获取类型
收费全文 | 704篇 |
免费 | 78篇 |
国内免费 | 218篇 |
专业分类
安全科学 | 68篇 |
废物处理 | 35篇 |
环保管理 | 58篇 |
综合类 | 411篇 |
基础理论 | 128篇 |
环境理论 | 2篇 |
污染及防治 | 185篇 |
评价与监测 | 53篇 |
社会与环境 | 25篇 |
灾害及防治 | 35篇 |
出版年
2024年 | 4篇 |
2023年 | 19篇 |
2022年 | 62篇 |
2021年 | 45篇 |
2020年 | 41篇 |
2019年 | 49篇 |
2018年 | 45篇 |
2017年 | 43篇 |
2016年 | 46篇 |
2015年 | 45篇 |
2014年 | 66篇 |
2013年 | 70篇 |
2012年 | 69篇 |
2011年 | 46篇 |
2010年 | 43篇 |
2009年 | 42篇 |
2008年 | 49篇 |
2007年 | 33篇 |
2006年 | 26篇 |
2005年 | 22篇 |
2004年 | 19篇 |
2003年 | 13篇 |
2002年 | 21篇 |
2001年 | 10篇 |
2000年 | 8篇 |
1999年 | 12篇 |
1998年 | 6篇 |
1997年 | 7篇 |
1996年 | 7篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有1000条查询结果,搜索用时 312 毫秒
201.
202.
离子色谱法同时测定有机和无机阴离子 总被引:2,自引:0,他引:2
用离子色谱法同时测定有机阴离子和无机阴离子,实验中采用一种新型高容量分离柱,灵敏度高,选择性好。讨论了最佳实验条件的选择测定了F^-,Cl^-,SO4^2-,NO2^-,SeO3^2-、C2O4^2-、甲酸奶和乙酸根等阴离子,并且分析了沈阳地区雪样中的几种阴离子。 相似文献
203.
204.
蚕豆微核、发光细菌急性毒性、鱼类急性毒性等实验基础上,采用PEEP(潜在的毒性效应)和CHIMIOTOX(预测毒性)等指数对6个重点行业的10家受试企业的工业废水生物综合毒性进行了监测与评价。结果表明,受试企业所排放废水的生物毒性均较大,迫切需要治理. 相似文献
205.
The EDTA effect on phytoextraction of single and combined metals-contaminated soils using rainbow pink (Dianthus chinensis) 总被引:4,自引:0,他引:4
Rainbow pink (Dianthus chinensis), a potential phytoextraction plant, can accumulate high concentrations of Cd from metal-contaminated soils. The soils used in this study were artificially added with different metals including (1) CK: original soil, (2) Cd-treated soil: 10 mg Cd kg(-1), (3) Zn-treated soil: 100 mg Zn kg(-1), (4) Pb-treated soil: 1000 mg Pb kg(-1), (5) Cd-Zn-treated soil: 10 mg Cd kg(-1) and 100 mg Zn kg(-1), (6) Cd-Pb-treated soil: 10 mg Cd kg(-1) and 1000 mg Pb kg(-1), (7) Zn-Pb-treated soil: 100 mg Zn kg(-1) and 1000 mg Pb kg(-1), and (8) Cd-Zn-Pb-treated soil: 10 mg Cd kg(-1), 100 mg Zn kg(-1), and 1000 mg Pb kg(-1). Three concentrations of 2Na-EDTA solutions (0 (control), 2, and 5 mmol kg(-1) soil) were added to the different metals-treated soils to study the influence of applied EDTA on single and combined metals-contaminated soils phytoextraction using rainbow pink. The results showed that the Cd, Zn, Pb, Fe, or Mn concentrations in different metals-treated soil solutions significantly increased after applying 5 mmol EDTA kg(-1) (p<0.05). The metal concentrations in different metals-treated soils extracted by deionized water also significantly increased after applying 5 mmol EDTA kg(-1) (p<0.05). Because of the high extraction capacity of both 0.005 M DTPA (pH 5.3) and 0.05 M EDTA (pH 7.0), applying EDTA did not significantly increase the Cd, Zn, or Pb concentration in both extracts for most of the treatments. Applying EDTA solutions can significantly increase the Cd and Pb concentrations in the shoots of rainbow pink (p<0.05). However, this was not statistically significant for Zn because of the low Zn concentration added into the contaminated soils. The results from this study indicate that applying 5 mmol EDTA kg(-1) can significantly increase the Cd, Zn, or Pb concentrations both in the soil solution or extracted using deionized water in single or combined metals-contaminated soils, thus increasing the accumulated metals concentrations in rainbow pink shoots. The proposed method worked especially well for Pb (p<0.05). The application of 2 mmol EDTA kg(-1) might too low to enhance the phytoextraction effect when used in silty clay soils. 相似文献
206.
207.
Chen KS Ho YT Lai CH Tsai YA Chen SJ 《Journal of the Air & Waste Management Association (1995)》2004,54(1):36-48
This work analyzes the variations in daily maximum 1-hr ozone (O3) concentrations and the long-term trends in annual means of hourly ambient concentrations of O3, nitrogen oxides (nitrous oxide + nitrogen dioxide), and nonmethane hydrocarbons in the three administrative regions of Kao-Ping airshed in southern Taiwan over a recent 8-yr period. The annual or monthly means of all maxima, most 95th percentiles, and some 90th percentiles of the daily maximum 1-hr O3 concentrations exceed the daily limit of 120 parts per billion by volume in all three regions, namely, Kao-hsiung City, Kso-hsiung County, and P'ing-tung County. The monthly means of daily maximum 1-hr O3 concentrations exhibit distinct seasonal variations, with a bimodal form with the maxima in autumn and late winter to the middle of spring and a minimum in summer. The long-term variations in the annual means of hourly O3 concentrations in the three regions exhibit increasing trends. These increases in O3 are associated with the decline in ambient concentrations of nitrogen oxides and nonmethane hydrocarbons. High O3 episodes occur most often in autumn and most rarely in summer. The seasonal mean mixing heights in descending order follow the order of spring, summer, autumn, and winter. Meteorological parameters in autumn and winter indicate that the ground-level O3 tends to accumulate and trigger a high O3 episode on a warm day with sufficient sunlight and low wind in a high-pressure system, consistent with the low mixing heights in these two seasons. 相似文献
208.
209.
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
210.
Profiles of PAH emission from steel and iron industries 总被引:5,自引:0,他引:5
In order to characterize the polycyclic aromatic hydrocarbons (PAHs) emission from steel and iron industries, this study measured the stack emission of twelve steel and iron plants in southern Taiwan to construct a set of source fingerprints. The study sampled the emissions by the USEPA's sampling method 5 with the modification of Graseby for the gas and particulate phase PAH and, then, used Hewlett-Packard 5890 gas chromatograph equipped with mass spectrometer detector to analyze the samples. The steel and iron industries are classified into three categories on the basis of auxiliary energy source: Category I uses coal as fuel, Category II uses heavy oil as fuel and Category III uses electric arc furnace. The pollution source profiles are obtained by averaging the ratios of individual PAH concentrations to the total concentration of 21 PAHs and total particulate matter measured in this study. Results of the study show that low molecular weight PAHs are predominant in gas plus particulate phase for all three categories. For particulate phase PAHs, however, the contribution of large molecular weight compounds increases. Two-ring PAHs account for the majority of the mass, varying from 84% to 92% with an average of 89%. The mass fractions of 3-, 4-, 5-, 6-ring PAHs in Category I are found to be more than those of the other two categories. The mass of Category III is dominated by 7-ring PAHs. Large (or heavy) molecular weight PAHs (HMW PAHs) are carcinogenic. Over all categories, these compounds are less than 1% of the total-PAH mass on the average. The indicatory PAHs are benz[a]anthracene, benzo[k]fluoranthene, benzo[ghi]perylene for Category I, benzo[a]pyrene, acenaphthene, acenaphthylene for Category II and coronene, pyrene, benzo[b]chrycene for Category III. The indicatory PAHs among categories are very different. Thus, dividing steel and iron industry into categories by auxiliary fuel is to increase the precision of estimation by a receptor model. Average total-PAH emission factors for coal, heavy oil and electric arc furnace were 4050 μg/kg-coal, 5750 μg/l-oil, 2620 μg/kW h, respectively. Carcinogenic benzo[a]pyrene for gas plus particulate phase was 2.0 g/kg-coal, 2.4 μg/l-oil and 1.4 μg/kW h for Category I, II and III, respectively. 相似文献