全文获取类型
收费全文 | 3408篇 |
免费 | 234篇 |
国内免费 | 1187篇 |
专业分类
安全科学 | 242篇 |
废物处理 | 211篇 |
环保管理 | 251篇 |
综合类 | 1994篇 |
基础理论 | 586篇 |
环境理论 | 2篇 |
污染及防治 | 1065篇 |
评价与监测 | 162篇 |
社会与环境 | 171篇 |
灾害及防治 | 145篇 |
出版年
2024年 | 10篇 |
2023年 | 76篇 |
2022年 | 190篇 |
2021年 | 195篇 |
2020年 | 153篇 |
2019年 | 99篇 |
2018年 | 156篇 |
2017年 | 166篇 |
2016年 | 179篇 |
2015年 | 199篇 |
2014年 | 296篇 |
2013年 | 342篇 |
2012年 | 288篇 |
2011年 | 303篇 |
2010年 | 212篇 |
2009年 | 215篇 |
2008年 | 242篇 |
2007年 | 162篇 |
2006年 | 186篇 |
2005年 | 148篇 |
2004年 | 89篇 |
2003年 | 111篇 |
2002年 | 81篇 |
2001年 | 85篇 |
2000年 | 102篇 |
1999年 | 86篇 |
1998年 | 87篇 |
1997年 | 76篇 |
1996年 | 72篇 |
1995年 | 57篇 |
1994年 | 44篇 |
1993年 | 32篇 |
1992年 | 43篇 |
1991年 | 13篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 8篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1966年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有4829条查询结果,搜索用时 15 毫秒
311.
不同运行模式对同步脱氮除磷CAST工艺快速启动及其稳定维持的影响 总被引:1,自引:0,他引:1
以实际生活污水为处理对象,考察了传统进水/曝气和改良型分段进水的交替缺氧-好氧(A/O)2种运行模式对CAST工艺的快速启动及脱氮除磷性能稳定维持的影响。结果表明,传统进水/曝气运行模式下,系统达到最佳营养物去除性能所需启动时间30 d,稳定运行阶段TN平均去除80.66%,磷的去除率维持在66.30%左右;采用改良型交替运行模式,反应器达到稳定运行状态仅需18 d,系统稳定运行时TN平均去除81.36%,磷去除率稳定维持在90%以上,出水磷浓度在0.3 mg/L以下,出水水质达到国家污水综合排放标准一级A(GB8978-2002)。研究还发现,传统运行模式下,由低温引起的污泥沉降性能变差导致系统污泥严重流失,反应器几乎丧失污染物去除性能;而低温对交替运行模式下的反应器除磷性能几乎没有影响,总氮去除则因氨氮不完全硝化而大大降低。 相似文献
312.
焙烧-酸浸法可有效回收电镀污泥中的有价金属,而污泥的热处理特性是决定能否采用焙烧预处理的重要因素。研究了氧化焙烧和还原焙烧对污泥成分和金属浸出性的影响,并对焙烧前后的污泥进行了金属形态分析和X射线衍射(XRD)分析。结果表明,焙烧预处理实现了污泥减量和金属富集;ES1经氧化焙烧后金属浸出率接近原泥,Cu的浸出率达99%;ES2的还原焙烧效果优于氧化焙烧,特别是Cu的浸出率超过97%,XRD分析发现,还原焙烧过程中金属Cu被还原为铁铜合金;2种焙烧均造成了ES3中目标金属Ni的浸出率的降低;金属浸出性的下降与残渣态的形成有关。 相似文献
313.
Jianshe Tang Min Zhang Guohua Cheng Ang Li Yitong Lu 《Journal of environmental science and health. Part. B》2013,48(8):707-712
Diethyl (carboxymethyl) phosphonate (DECP) was used as the hapten to develop an indirect competitive enzyme-linked immunosorbent assay (IC-ELISA) for detecting organophosphorus pesticides (OPs). Conjugator of DECP with bovin serum albumin (BSA) was used as the immunogen for producing the polyclonal antibodies (PcAbs). Three antisera were obtained after the immune procedure. Characterization studies of the PcAbs indicated that the titer of antiserum-1 was highest in 3 antisera, and antiserum-1 had high affinity and specificity to the parathion, dichlorvos and pirimiphos. The IC-ELISA showed an IC50 of 0.428 μ g/mL with a detection limit of 0.0125 μ g/mL to parathion. The assay also indicated that the IC50 values of pirimiphos and dichlorvos were 0.331 μ g/mL and 1.25 μ g/mL respectively, and the detection limits of pirimiphos and dichlorvos were 0.0116 μ g/mL and 0.048 μ g/mL respectively. Recoveries of parathion, pirimiphos and dichlorvos spiked into water samples ranged from 90% to 160%. The results indicated that the ELISA could be a convenient and supplemental analytical tool for monitoring OPs residues in environmental water samples. 相似文献
314.
Pablo Souza-Alonso Alejandra Guisande Luís González 《Journal of environmental science and health. Part. B》2013,48(3):184-189
Triclopyr is a commonly used herbicide in the control of woody plants and can exhibit toxic effects to soil microorganisms. However, the impact on soils invaded by plant exotics has not yet been addressed. Here, we present the results of an 18-month field study conducted to evaluate the impact of triclopyr on the structure of fungal and bacterial communities in soils invaded by Acacia dealbata Link, through the use of denature gradient gel electrophoresis. After triclopyr application, analyses of bacterial fingerprints suggested a change in the structure of the soil bacterial community, whereas the structure of the soil fungal community remained unaltered. Bacterial density and F:B ratio values changed across the year but were not altered due to herbicide spraying. On the contrary, fungal diversity was increased in plots sprayed with triclopyr 5 months after the first application. Richness and diversity (H´) of both bacteria and fungi were not modified after triclopyr application. 相似文献
315.
Judith C. Chow John G. Watson Richard T. Egami Clifton A. Frazier Zhiqiang Lu Andrew Goodrich 《Journal of the Air & Waste Management Association (1995)》2013,63(8):1134-1142
Street sweeping is often proposed as a means of reducing the emissions from paved roads. The objective of this study was to evaluate the effectiveness of street sweeping on ambient particulate matter concentrations and to determine the difference In source contributions to PM10 concentrations between street sweeping and non-street sweeping periods. Chemically-speciated measurements of PM10 and PM2.5 were taken in the commercial section of Reno, Nevada, for a one-month sampling period. The Chemical Mass Balance (CMB) model was applied to these data and an average of approximately 50 percent of the PM10 was apportioned to resuspended geological material. During half of the sampling period, streets In the vicinity of the sampling site were completely swept with a regenerative-air vacuum sweeper, while no sweeping was performed during the remainder of the experiment. Ratios of primary geological contributions divided by primary motor vehicle contributions to PM10 were compared between sweeping and non-sweeping periods using analysis of variance. This ratio of source contributions minimizes the effects of variations in traffic volume and meteorological dispersion. No significant differences in geological contributions to PM10 were detected as a result of regenerative-air vacuum street sweeping. 相似文献
316.
V. A. Cundy C. Lu C. A. Cook A. M. Sterling C. B. Leger A. L. Jakway 《Journal of the Air & Waste Management Association (1995)》2013,63(8):1084-1094
Comparisons are made, for the first time, between the combustion characteristics of dichloromethane and xylene in an industrial rotary kiln incinerator. The comparisons are made under different operating conditions, including variable kiln rotation rate and operation both with and without turbulence air. Continuous gas composition and temperature measurements and batch gas composition measurements were obtained from two vertical locations hear the exit region of the rotary kiln. The measurements show that there is significant vertical stratification at the exit of the kiln. Addition of turbulence air enhanced combustion conditions throughout the kiln during xylene processing. During dichloromethane processing, however, the addition of turbulence air had minimal effect and only promoted greater bulk mixing; chlorinated compounds transported from the lower kiln during operation with turbulence air were not efficiently processed in the upper kiln. Evolution of test liquids from the bed was not constant but rather was characterized by intermittent peaks. The field-scale data of this work suggest that the evolution rate of the test liquid was increased as kiln rotation rate increased. Many of the differences between xylene and dichloromethane processing during these experiments are explained by a simple stoichiometric analysis. 相似文献
317.
Ming-Shean Chou Shu-Ling Lu 《Journal of the Air & Waste Management Association (1995)》2013,63(8):711-720
ABSTRACT This paper presents results obtained from a performance study on the biotreatment of 1,3-butadiene in an air stream using a reactor that consisted of a two-stage, in-series biotrickling filter connected with a three-stage, in-series biofilter. Slags and pig manure-based media were used as packing materials for the biotrickling filter and the biofilter, respectively. Experimental results indicated that, for the biotrickling filter portion, the butadiene elimination capacities were below 5 g/m3/hr for loadings of less than 25 g/m3/hr, and the butadiene removal efficiency was only around 17%. For the biofilter portion, the elimination capacities ranged from 10 to 107 g/m3/hr for loadings of less than 148 g/m3/hr. The average butadiene removal efficiency was 75–84% for superficial gas velocities of 53–142 m/hr and a loading range of 10–120 g/m3/hr. The elimination capacity approached a maximum of 108 g/m3/hr for a loading of 150 g/m3/hr. The elimination rates of butadiene in both the biotrickling filter and biofilter were mass-transfer controlled for influent butadiene concentrations below about 600 ppm for superficial gas velocities of 29–142 m/hr. The elimination capacity was significantly higher in the biofilter than in the biotrickling filter. This discrepancy may be attributed to the higher mass-transfer coefficient and gas-solid interfacial area offered for transferring the gaseous butadiene in the biofilter. 相似文献
318.
Isaac R. Kaplan Shan-Tan Lu Hossein M. Alimi John MacMurphey 《Environmental Forensics》2013,14(3):231-248
Fingerprinting of hydrocarbon products requires high resolution differentiation of individual hydrocarbon compounds in any mixture. This requires the applications of various measuring techniques. In this paper, we have chosen the heavy hydrocarbons in fuels, lubricants and paving material as examples to discuss the methods for chemical characterization and differentiation. In the category most frequently termed "semi-volatile hydrocarbons" with boiling points from about 500°F to 1200°F or higher, there are several families of hydrocarbons, both natural and refined that are not easily distinguished by conventional EPA tests. Among the groups which we will use as examples are asphalts, hydraulic fluid, transmission oil, motor lubricating oils, heating oils, crude oil and coal. These hydrocarbon families are best studied using combined gas chromatography-mass spectrometry in full scan mode and characterizing various homologous series of hydrocarbons at known fragment ions. The hydrocarbon series providing the best information are: (1) N -alkanes; (2) iso-alkanes; (3) steranes; (4) terpanes; (5) polynuclear aromatic hydrocarbons; (6) aromatic steranes; and (7) specific polycyclic compounds. 相似文献
319.
The REDD+ (Reducing Emissions from Deforestation and Forest Degradation) partnership works to promote the reduction of greenhouse gas (GHG) emissions by protecting forests in developing countries through positive incentives. It is regarded as an essential component of the post‐2012 climate regime to stabilize GHG emissions and engage developing countries in worldwide mitigation endeavours. This study focuses on the gap between agricultural revenue and REDD+ compensation through the construction of several scenarios that explore the impacts of possible carbon price ranges.Three scenarios that reflect different potential policies are examined: (1) current carbon trading; (2) carbon trading with all forestry activities; and (3) carbon trading with all countries participating gradually over the coming decades. Data for developing the scenarios were obtained through a case study in central Kalimantan, Indonesia, by interrogating the potential for revenue by expanding agricultural land. The results indicate that REDD+ payments could not effectively compensate land users for their opportunity cost of deforestation, making it difficult for the governments to ensure that REDD+ money “reaches the ground” in terms of balancing the agricultural revenue of land users. 相似文献
320.