全文获取类型
收费全文 | 860篇 |
免费 | 3篇 |
国内免费 | 3篇 |
专业分类
安全科学 | 16篇 |
废物处理 | 17篇 |
环保管理 | 136篇 |
综合类 | 269篇 |
基础理论 | 149篇 |
污染及防治 | 200篇 |
评价与监测 | 47篇 |
社会与环境 | 25篇 |
灾害及防治 | 7篇 |
出版年
2020年 | 7篇 |
2018年 | 16篇 |
2017年 | 10篇 |
2016年 | 16篇 |
2015年 | 13篇 |
2014年 | 20篇 |
2013年 | 68篇 |
2012年 | 23篇 |
2011年 | 33篇 |
2010年 | 23篇 |
2009年 | 22篇 |
2008年 | 33篇 |
2007年 | 36篇 |
2006年 | 19篇 |
2005年 | 22篇 |
2004年 | 36篇 |
2003年 | 19篇 |
2002年 | 24篇 |
2001年 | 12篇 |
2000年 | 13篇 |
1999年 | 18篇 |
1998年 | 8篇 |
1997年 | 12篇 |
1996年 | 17篇 |
1995年 | 12篇 |
1994年 | 25篇 |
1993年 | 7篇 |
1991年 | 7篇 |
1990年 | 8篇 |
1988年 | 6篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1981年 | 8篇 |
1980年 | 9篇 |
1979年 | 7篇 |
1978年 | 7篇 |
1977年 | 7篇 |
1968年 | 6篇 |
1965年 | 6篇 |
1964年 | 9篇 |
1963年 | 6篇 |
1962年 | 6篇 |
1961年 | 6篇 |
1960年 | 8篇 |
1959年 | 11篇 |
1957年 | 7篇 |
1956年 | 11篇 |
1954年 | 9篇 |
1939年 | 6篇 |
1924年 | 6篇 |
排序方式: 共有866条查询结果,搜索用时 15 毫秒
401.
Sun H Gerecke AC Giger W Alder AC 《Environmental pollution (Barking, Essex : 1987)》2011,159(2):654-662
This study focused on the occurrence of long-chain perfluorinated chemicals (PFCs) in anaerobically stabilized sewage sludges from 20 municipal WWTPs using current and historic samples to evaluate the levels of PFCs and to identify the relative importance of commercial and industrial sources. A quantitative analytical method was developed based on solvent extraction of the analytes and a LC-MS/MS system. For total perfluoralkyl carboxylates (PFCAs), the concentrations ranged from 14 to 50 μg/kg dry matter. Concentrations of perfluorooctane sulfonic acid (PFOS) ranged from 15 to 600 μg/kg dry matter. In three WWTPs, the PFOS levels were six to nine times higher than the average values measured in the other plants. These elevated PFOS concentrations did not correlate with higher levels of PFCAs, indicating specific additional local sources for PFOS at these WWTPs. Average concentrations in selected samples from the years 1993, 2002, and 2008 did not change significantly. 相似文献
402.
Nonylphenols and nonylphenolethoxylates with one, two, and three oxyethylene groups were identified in effluents from activated sludge sewage treatment plants. The complex mixtures of isomers are considered to be refractory metabolites of nonionic detergents. 相似文献
403.
Walter Debruyn Gilbert Lissens Jan van Rensbergen Maria Wevers 《Environmental monitoring and assessment》1994,31(1-2):159-165
The estimation of nitrous oxide emissions is complicated by the high degree of uncertainty on the emission factors involved and by the limited acquaintance with all significant nitrous oxide sources. A potentially important source for which emission data are lacking is the sewage system transporting waste water from human activities. For this study an experimental measurement campaign has been carried out on waste water sampled at different sewage treatment plants. The nitrous oxide developing from the water samples was monitored by means of gas chromatography. The methodological analysis was based on the concentration/time curves obtained. Our results indicate that the formation of nitrous oxide from the waste water matrices results from microbiological denitrification. We deduced tentative emission factors for the waste water types studied. 相似文献
404.
Kenneth M. Doll Erin L. Walter Rex E. Murray 《International Journal of Sustainable Engineering》2018,11(1):26-31
The ruthenium sawhorse has proven effective in the conversion of trans-cinnamic acid, and substituted trans-cinnamic acids, giving an effective source of biobased styrene and styrene analogues. The reaction is especially versatile, as it achieves product without utilising co-reagents. However, the optimum conditions and substrate scope of the reaction remain unexplored. This report covers the decarboxylation of a series of cinnamates with different structures. Apparent activation energies ranging from 66 to 142 kJ mol?1 were uncovered. 相似文献
405.
Understanding the climate and its variability, in particular with regard to their socioeconomic impact, requires specific measurements of precipitation and temperature and their circulations. This becomes more important in applications to diverse systems. In order to improve knowledge about temporal changes and trends in temperature, we analyzed series of maximum and minimum daily surface temperatures at eight reference stations in southeastern South America during variable periods, with the longest periods of around 100 years. To study the evolution of the temperature series and to reduce the number of parameters, a nonhierarchical cluster analysis was performed. The algorithm assigns each day to one of four groups: warm, wet, cold and dry. Low frequency variations were found in these groups and their association with circulation structure, circulation patterns and precipitation. We concluded that the set of wet days is one of the main factors driving secular variations of maximum and minimum temperature and variations in precipitation. We also inferred that after 1920 till 1930, a low frequency oscillation is observed in the form of linear trends (increase of warm days and decrease of cold days). 相似文献
406.
407.
Rosenfelder N Bendig P Vetter W 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2706-2712
Polybrominated diphenyl ethers (PBDEs) are frequently detected in food and environmental samples. We used compound specific isotope analysis to determine the δ13C values of individual PBDEs in two technical mixtures. Within the same technical product (DE-71 or DE-79), BDE congeners were the more depleted in 13C the higher brominated they were. In contrast, the products of light-induced hydrodebromination of BDE 47 and technical DE-79 were more enriched in 13C because of more stable bonds between 13C and bromine. As a result, the δ13C values of the irradiated solution progressed diametrically compared to those of the technical synthesis. The ratio of the δ13C values of BDE 47 to BDE 99 and of BDE 99 to BDE 153 are thus suggested as indicators to distinguish native technical products from transformation products. Ratios <1 are typical for native congeners (e.g. in DE-71) while the reversed ratio (>1) is typical of transformation products. 相似文献
408.
Sponges of warm- and temperate- but also cold-waters are known to synthesize structurally diverse primary and secondary metabolites.
These compounds fulfill a variety of functions including adaptations of the cell membranes to environmental conditions. We
show here that boreal sponges of the order Halichondrida are rich sources of brominated lipid fatty acids. The comparison
of lipid compositions of halichondrid Demospongiae from boreal and warmer waters indicates an accumulation of brominated fatty
acids in sponges from colder settings. Moreover, the spatial distribution of brominated fatty acids in the sponge tissue of
one widely distributed sponge of the North-East Atlantic (Phakellia ventilabrum) hints to a function related to membrane fluidity and permeability rather than to defense against predation. However, brominated
fatty acids are diagnostic for the presence of bromoperoxidases in sponges and may therefore be potentially useful as markers
in a chemical screening for secondary metabolites of pharmacological interest. 相似文献
409.
Summary. Individual variations in pheromone emission patterns were examined in a scarab beetle, Anomala cuprea Hope (Coleoptera: Scarabaeidae), by headspace collection of airborne volatiles from individual females. The amount of pheromone
obtained varied among virgin females, and about 16% of these females (“silent” females) did not emit detectable amount of
pheromone throughout the experimental period. There was no clear temporal pattern of peak pheromone emission for 19 days after
the onset. More than half of the laboratory mated females completely stopped releasing pheromone after the first mating, while
the rest of them continued releasing pheromone, frequently followed by additional mating.
Received 26 March 2001; accepted 28 January 2002. 相似文献
410.