全文获取类型
收费全文 | 290篇 |
免费 | 1篇 |
国内免费 | 8篇 |
专业分类
安全科学 | 17篇 |
废物处理 | 10篇 |
环保管理 | 44篇 |
综合类 | 49篇 |
基础理论 | 54篇 |
污染及防治 | 84篇 |
评价与监测 | 19篇 |
社会与环境 | 19篇 |
灾害及防治 | 3篇 |
出版年
2023年 | 8篇 |
2022年 | 13篇 |
2021年 | 18篇 |
2020年 | 8篇 |
2019年 | 4篇 |
2018年 | 5篇 |
2017年 | 9篇 |
2016年 | 6篇 |
2015年 | 8篇 |
2014年 | 9篇 |
2013年 | 36篇 |
2012年 | 9篇 |
2011年 | 12篇 |
2010年 | 11篇 |
2009年 | 14篇 |
2008年 | 11篇 |
2007年 | 15篇 |
2006年 | 15篇 |
2005年 | 12篇 |
2004年 | 6篇 |
2003年 | 10篇 |
2002年 | 3篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 1篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1987年 | 1篇 |
1986年 | 4篇 |
1985年 | 1篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1973年 | 2篇 |
1955年 | 1篇 |
1938年 | 1篇 |
1933年 | 1篇 |
1931年 | 2篇 |
1926年 | 1篇 |
1920年 | 1篇 |
排序方式: 共有299条查询结果,搜索用时 406 毫秒
281.
This study compared the swine wastewater treatment of two identical lab-scale two-stage sequencing batch reactors (TSSBR) under similar conditions except that one was operated on a fixed-time mode and the other on a real-time mode. While both TSSBR systems performed very well, the real-time TSSBR performed far better then the fixed-time TSSBR, in every aspect of carbon, nitrogen, and phosphorous removal. The removals of COD, TOC, were at 97% and for BOD5 even at 99.7%. In terms of NH4-N and TKN removals, the real-time TSSBR achieved removal of over 98%. For phosphorus removals (Ortho-P and total P) the results from the real-time TSSBR was quite remarkable at 97.7%. 相似文献
282.
Cheuk W Lo KV Branion RM Fraser B 《Journal of environmental science and health. Part. B》2003,38(6):855-863
This study investigated the benefits of an on-site sustainable solid waste treatment and utilization system for the greenhouse industry. The composts made from greenhouse wastes were tested and found to contain high nutrient values and good physical properties, and could be used as high quality growing media. The finished composts were tested in a greenhouse against the conventional growth media (sawdust) and resulted in a 10% yield increase by using the compost. An economic analysis was conducted to show the economic benefits of on-site composting for a greenhouse operation. Based on a four-hectare tomato or pepper greenhouse, and amortizing the capital equipment over five years, the net annual cost of composting represents a savings of dollars 8,000 annually. 相似文献
283.
Victor F. Weisskopf 《Die Naturwissenschaften》1985,72(12):648-653
284.
Concentrations of silver, cadmium, chromium, iron, manganese, nickel, lead, vanadium, and zinc were determined in dust fallout samples from eight inland locations in Kuwait. Results were used to calculate enrichment factors for metals relative to their abundance in the continental crust using Fe as the conservative element. Five metals (Cu, Cr, Mn, Ni, and V) showed enrichment factors that were approximately unity (1.3–4.7). Higher enrichment factors for the rest (24–421) suggested an anthropogenic contribution for Ag, Cd, Pb, and Zn. However, all metals in dust fallout (except Pb and Zn) showed a degree of enrichment relative to unpolluted marine sediments that was approximately unity, suggesting a substantial aeolian contribution to trace metals in marine surface sediments. Higher enrichments for Pb and Zn probably reflect a larger input from local pollution sources. This is particularly true for lead, the enrichment of which showed a stronger association with the distribution of urban population. Probable contributions of aeolian transport to a band of elevated lead concentrations in marine surface sediments are discussed. 相似文献
285.
Calculation of clothing insulation by serial and parallel methods: effects on clothing choice by IREQ and thermal responses in the cold. 总被引:1,自引:0,他引:1
Kalev Kuklane Chuansi Gao Ingvar Holmér Lina Giedraityte Peter Br?de Victor Candas Emiel den Hartog Harriet Meinander Mark Richards George Havenith 《International journal of occupational safety and ergonomics》2007,13(2):103-116
Cold protective clothing was studied in 2 European Union projects. The objectives were (a) to examine different insulation calculation methods as measured on a manikin (serial or parallel), for the prediction of cold stress (IREQ); (b) to consider the effects of cold protective clothing on metabolic rate; (c) to evaluate the movement and wind correction of clothing insulation values. Tests were carried out on 8 subjects. The results showed the possibility of incorporating the effect of increases in metabolic rate values due to thick cold protective clothing into the IREQ model. Using the higher thermal insulation value from the serial method in the IREQ prediction, would lead to unacceptable cooling of the users. Thus, only the parallel insulation calculation method in EN 342:2004 should be used. The wind and motion correction equation (No. 2) gave realistic values for total resultant insulation; dynamic testing according to EN 342:2004 may be omitted. 相似文献
286.
Genwen Zhou J. L. Willett Craig J. Carriere Y. Victor Wu 《Journal of Polymers and the Environment》2000,8(3):145-150
The effect of starch granule size on the viscosity of starch-filled poly(hydroxy ester ether) (PHEE) composites was characterized using size-fractionated potato starch, as well as unfractionated starches (rice, corn, wheat, and potato). Potato starch was separated using an air classifier into four particle size fractions: <18 m, 18-24 m, 24-30 m, and >30 m. The starch was dried to a moisture content of 0.5% to minimize moisture effects on composite rheology. PHEE and potato starch were extruded with starch volume fractions of 0.46 and 0.66. Stress relaxation, frequency and strain sweep, and temperature-dependence measurements were carried out. Although small variations in viscosity were seen with the different potato starch fractions, differences were not significant at a volume fraction of 0.46. Viscosity differences between the different particle size fractions were more pronounced at a volume fraction of 0.66. The temperature dependence could be described by an Arrhenius relation, with an apparent activation energy of 84 kJ/mole. At a volume fraction of 0.46, the starch/PHEE viscosities increased in the order potato starch < wheat starch corn starch < rice starch. 相似文献
287.
Victor W. Lambou Stephen C. Hern William D. Taylor Llewellyn R. Williams 《Journal of the American Water Resources Association》1982,18(5):807-813
ABSTRACT: The relationship between chlorophyll u, total phosphorus, secchi disk depth, and trophic state were examined using data on U.S. lakes collected by U.S. EPA's National Eutrophication Survey. By comparing predicted secchi disk depths with observed summer secchi disk depths in 757 lakes, it was determined that in many lakes non-chlorophyll related light attenuation is important in controlling the amount of chlorophyll u produced per unit of total phosphorus. Ranking of 44 lakes by 18 different trophic state measurements and single and multivariable indices were compared with rankings provided by mean summer ambient total phosphorus and chlorophyll u. The trophic state measurements and indices were much more successful in ranking the lakes against total phosphorus than chlorophyll u, indicating that there are differences in the relative trophic rankings of many of the lakes depending upon whether primary nutrients or biological manifestations are used as the ranking mechanism. If the manifestations of nutrients rather than their absolute levels are the primary criteria for beneficial use of lakes, the use of many of the commonly employed trophic state measurements, which assume or imply that there is a constant relationship between total phosphorus or secchi disk and chlorophyll, can lead to erroneous conclusions and unnecessary costly management controls. Secchi disk measurements may be more useful as a predictor of ambient lake total phosphorus concentrations than of chlorophyll. 相似文献
288.
In anaerobic digestion, the production of short-chain fatty acids (SCFAs) can be beneficial or harmful to the overall process, depending on the concentration of accumulated acids. Therefore, the accurate determination of the SCFA concentration in both fresh and stored sludge hydrolysates is important. To select a suitable method for monitoring SCFAs during the anaerobic digestion of sewage sludge, the accuracy of three available analytical methods, including 5 pH point acid titration (TITRA5), gas chromatography (GC), and spectrophotometry, were compared in the present study. The results revealed that TITRA5 and GC displayed better agreement in the achieved measurements and higher precision and accuracy than the spectrophotometric assay, as supported by the application of different statistical models. TITRA5 excelled in titrating unfiltered hydrolysate while simultaneously measuring the alkalinity, whereas the GC method provided detailed information on the contribution of different fatty acids to the total acidity. In contrast, the spectrophotometric assay suffered from many forms of interference, depending on the sample's matrix. SCFA production followed the pattern of enzymatic reactions and fitted the Michaelis-Menten model. In addition to promoting TITRA5 as an accurate and robust analytical tool for routine SCFA analyses, this comparative study also demonstrated the possibility of storing hydrolysate samples at different temperatures and durations without altering the SCFA measurements. 相似文献
289.
290.
Victor Bandaly Aurélie Joubert Pierre Le Cann Yves Andres 《Food and environmental virology》2017,9(4):464-472
One of the most important topics that occupy public health problems is the air quality. That is the reason why mechanical ventilation and air handling units (AHU) were imposed by the different governments in the collective or individual buildings. Many buildings create an artificial climate using heating, ventilation, and air-conditioning systems. Among the existing aerosols in the indoor air, we can distinguish the bioaerosol with biological nature such as bacteria, viruses, and fungi. Respiratory viral infections are a major public health issue because they are usually highly infective. We spend about 90% of our time in closed environments such as homes, workplaces, or transport. Some studies have shown that AHU contribute to the spread and transport of viral particles within buildings. The aim of this work is to study the characterization of viral bioaerosols in indoor environments and to understand the fate of mengovirus eukaryote RNA virus on glass fiber filter F7 used in AHU. In this study, a set-up close to reality of AHU system was used. The mengovirus aerosolized was characterized and measured with the electrical low pressure impact and the scanner mobility particle size and detected with RT-qPCR. The results about quantification and the level of infectivity of mengovirus on the filter and in the biosampler showed that mengovirus can pass through the filter and remain infectious upstream and downstream the system. Regarding the virus infectivity on the filter under a constant air flow, mengovirus was remained infectious during 10 h after aerosolization. 相似文献