全文获取类型
收费全文 | 119篇 |
免费 | 2篇 |
专业分类
安全科学 | 9篇 |
废物处理 | 7篇 |
环保管理 | 11篇 |
综合类 | 11篇 |
基础理论 | 15篇 |
环境理论 | 1篇 |
污染及防治 | 58篇 |
评价与监测 | 6篇 |
社会与环境 | 3篇 |
出版年
2022年 | 1篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2017年 | 1篇 |
2016年 | 5篇 |
2015年 | 3篇 |
2014年 | 8篇 |
2013年 | 5篇 |
2012年 | 11篇 |
2011年 | 6篇 |
2010年 | 2篇 |
2009年 | 3篇 |
2008年 | 7篇 |
2007年 | 6篇 |
2006年 | 8篇 |
2005年 | 8篇 |
2004年 | 7篇 |
2003年 | 7篇 |
2002年 | 4篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有121条查询结果,搜索用时 6 毫秒
21.
The effect of urea on PCDD/F formation in a pilot incinerator was studied by incinerating urea with refuse-derived fuel (RDF) at three concentrations (0.1%, 0.5% and 1.0%, of the fuel feed). A distinct reduction in both PCDD/F and chlorophenol concentrations could be noticed when urea was introduced into the system. Partial-least-square (PLS) analysis of the data showed the importance of certain chlorophenol isomers as PCDD/F precursors, pointing to the possibility that the impact point of the urea inhibitor could be before the precursor molecules, i.e. chlorophenols, have been formed. 相似文献
22.
Management of pikeperch migrating over management areas in a Baltic archipelago area 总被引:2,自引:0,他引:2
Pikeperch Sander lucioperca (L.) were tagged in an area where ten small independent management units regulate fisheries, in order to analyze the relevance of migrations for the management. A total of 465 fishes were tagged in connection with the spawning migration. The number of recaptures was 96. The distribution of recaptures between areas and that of total catches, estimated from questionnaire to housholds and, individuals in the survey area, were correlated. The comparison of tagging and recapture dates showed that the same pikeperch migrated to the spawning areas at the same time in two subsequent years, indicating the existence of individual spawning behavior. A modified yield/recruit-model demonstrated that in situations where the dispersal area of a pikeperch stock overlaps with several management areas, the risk of overfishing is very high. Management of this kind of fisheries needs cooperation between units as well as sound data on the movements of pikeperch to define the effects of fishing regulations. 相似文献
23.
24.
Catalytic water phase processes as an environmental application is a relatively novel subject with tremendous potential in the near future. This review of 120 references presents the wide scale of heterogeneous water phase applications studied mainly within past five years. Both oxidation and hydrogenation processes are included as well as TiO2 assisted photocatalysis. According to the references, heterogeneous catalysis is developing rapidly. New bimetallic catalysts and supports with higher surface area have improved catalytic efficiency in both oxidation and hydrogenation processes. It also seems that study on use of some waste materials such as red mud as catalyst is a very progressive field. On the whole, the chemical aspects are pretty well known, but the catalyst durability, and in many cases activity as well, has to be improved. 相似文献
25.
Repeatability,Sensitivity, and Uncertainty Analyses of the BANCS Model Developed to Predict Annual Streambank Erosion Rates
下载免费PDF全文
![点击此处可从《Journal of the American Water Resources Association》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Kari A. Bigham Trisha L. Moore Jason R. Vogel Tim D. Keane 《Journal of the American Water Resources Association》2018,54(2):423-439
Accelerated streambank erosion caused by channel instability can be the leading cause of sediment impairment of streams. Obtaining accurate streambank erosion rates for sediment budgeting and prioritizing mitigation efforts can be difficult and costly. One approach to quantifying streambank erosion rates is through the development and implementation of an empirically derived “Bank Assessment for Non‐point Source Consequences of Sediment” (BANCS) model. This study aims to improve the BANCS model application by evaluating repeatability between users and identifying sensitive and/or uncertain model inputs. Statistical analysis of streambank evaluations conducted by 10 different individuals suggests the implementation of the BANCS model may not be repeatable. This finding may be due to sensitive model inputs, such as streambank height and near‐bank stress level prediction method selection, and/or uncertain model inputs, such as bank material identification and the associated adjustment of erosion potential. Furthermore, it was found assessing streambanks as a group by obtaining a measure of central tendency from individual evaluations, as well as obtaining a higher level of training, may improve model implementation precision. Application of these suggestions may result in improved prediction of streambank erosion rates utilizing the BANCS model methodology. 相似文献
26.
Ruchi Jain Seshagiri Raghukumar Kari Sambaiah Yasuyuki Kumon Toro Nakahara 《Marine Biology》2007,151(5):1657-1664
Thraustochytrid protists characteristically accumulate high amounts of lipids, much of which is comprised of the polyunsaturated
fatty acid, docosahexaenoic acid (DHA). Since DHA is important in human health, thraustochytrids have attracted much attention
from the point of view of biotechnology. However, the biological rationale of DHA production in the storage lipids of these
organisms is not clear. We carried out three experiments to study this. (1) The fate of lipids in thraustochytrids during
development was studied by staining lipids of vegetative cells with the fluorescent vital stain for lipids, namely Nile blue,
following the growth of the cells. The fluorescent lipid bodies decreased in abundance in freshly formed motile limaciform
amoeboid cells and subsequently disappeared when they moved away. When vegetative cells produced vast extensions of plasma
membrane, the ectoplasmic net elements (EN), the fluorescent lipids appeared to be transported to them. (2) Changes in lipids
and DHA during starvation were examined in cells with enhanced lipid and DHA contents and those in which they were not enhanced.
Cells in which lipids and DHA were enhanced by refrigerating them for 48 h survived starvation for a longer period. Compared
to cells that had not been refrigerated, total fatty acids, as well as DHA were marginally higher in pre-refrigerated cells,
while palmitic acid levels were lower. Starvation of cells resulted in a gradual decrease of absolute concentrations and percentage
levels of DHA after 8 days, while percentage of palmitic acid levels increased. (3) The relationship between DHA and specific
gravity of cells was studied by comparing cells pre-refrigerated as above with those which were not pre-refrigerated. Refrigerated
cells with increased lipids and DHA showed higher specific gravities than non-refrigerated cells. We suggest the following
roles for storage lipids and DHA in thraustochytrids: (1) lipids serve as energy sources during movement of cells and for
production of EN; (2) DHA in storage lipids become distributed in the plasma membrane when EN are formed; (3) DHA is preferably
utilized as a fatty acid energy reserve during starvation and (4) an unknown mechanism results in negative buoyancy of cells
when total lipids and DHA are marginally enhanced. DHA in storage lipids might be crucial to the survival of thraustochytrid
cells. 相似文献
27.
Summary Nest defence responses of experimentally naive and revisited willow tits (Parus montanus) towards a predator model were studied near Oulu, northern Finland, in 1988–1989. Intensity was measured with three variables in 228 trials at 90 nests. Two hypotheses explaining the temporal changes in the nest defence behavior were examined. In naive birds the nest defence intensity was positively correlated with the brood age, supporting the parental investment hypothesis. The number of previous trials did not cause additional variation in nest defence behavior in comparison between naive and revisited birds. Similarly, experiences in a previous breeding attempt did not affect the nest defence behavior during the course of the subsequent brood. Thus, the temporal increase in multiply visited nests was not due to the birds becoming familiar with the nest threat, i.e., no support was found for the so-called positive reinforcement hypothesis. We think that methodological problems in avian nest defence studies can hide the adaptive significance of the behavior, not explain it.
Offprint requests to: S. Rytkönen 相似文献
28.
The OECD monitoring programmes 1966–1971 and 1972–1975 have been extended at national level in Finland to 1983 by analysing chlorinated hydrocarbons, mercury and chlorophenols in starlings (terrestrial environment). At the end of the study period levels in fresh muscles were for DDE 10, PCB 30, HCB 1, Lindan 8 and mercury 50 ppb. Of chlordane residues only traces of oxychlordane were found. Ten different chlorophenol compounds were detected at ppb levels, but most of them in only few samples. Pentachlorophenol was most frequently found. Statistical treatment of the analysis results gave some decreasing trends which were very significant for DDE, DDT and PCB 1967–1983, significant for mercury 1967–1983 and somewhat significant for lindane 1978–1983. 相似文献
29.
Accurate predictions of 13C NMR chemical shifts (standard error approximately 1.7 ppm) are achieved for a subset of chlorinated bornanes by empirical scaling of shifts from GIAO calculations with geometries obtained from HF/6-31G* calculations. The optimized molecular geometries were compared with X-ray structures for three of the toxaphene components most frequently detected in environmental samples (Parlar nos. 26, 50 and 62), and the concordance between the experimental and calculated values was found to be satisfactory. Taken overall, the results indicate that theoretical methods hold great promise for rationalizing 13C NMR chemical shifts in organohalogen compounds. However, it appeared that the DFT/GIAO shifts need to be empirically scaled to achieve good numerical agreement with experimental shifts in chlorinated bornanes. Obviously, there is a need to develop new computational methods to describe the large deshielding effects of chlorine atoms properly. 相似文献
30.
Urea as a PCDD/F inhibitor in municipal waste incineration 总被引:2,自引:0,他引:2
Ruokojärvi P Asikainen A Ruuskanen J Tuppurainen K Mueller C Kilpinen P Yli-Keturi N 《Journal of the Air & Waste Management Association (1995)》2001,51(3):422-431
Emissions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from municipal waste incineration have been widely studied because of their extensive toxicity, and many efforts have been made to restrict their emissions. Although a number of chemical compounds have been shown in laboratory-scale tests to inhibit the formation of PCDD/Fs, few have been tested in pilot- or full-scale plants. This work evaluates the effect of urea as a PCDD/F inhibitor in a pilot-scale incinerator that uses refuse-derived fuel (RDF). The decomposition of urea under the test conditions was also studied using detailed kinetic modeling. An aqueous solution of urea was injected into the flue gas stream after the furnace at approximately 730 degrees C, with varied urea concentrations and flue gas residence times used between the furnace and the sampling point. The results demonstrate that urea can successfully inhibit PCDD/F formation in waste incineration if concentrations and injection points are properly adjusted. The kinetic model showed that urea can be rapidly decomposed under appropriate flue gas conditions, indicating that in addition to the urea molecule itself, decomposition products of urea can also be responsible for the reduction of PCDD/F production during incineration. 相似文献