全文获取类型
收费全文 | 150篇 |
免费 | 3篇 |
专业分类
安全科学 | 3篇 |
废物处理 | 8篇 |
环保管理 | 24篇 |
综合类 | 44篇 |
基础理论 | 28篇 |
污染及防治 | 35篇 |
评价与监测 | 3篇 |
社会与环境 | 8篇 |
出版年
2023年 | 1篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 5篇 |
2016年 | 3篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 7篇 |
2012年 | 9篇 |
2011年 | 9篇 |
2010年 | 3篇 |
2009年 | 8篇 |
2008年 | 7篇 |
2007年 | 6篇 |
2006年 | 9篇 |
2005年 | 3篇 |
2004年 | 8篇 |
2003年 | 6篇 |
2002年 | 7篇 |
2001年 | 8篇 |
2000年 | 1篇 |
1999年 | 4篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1981年 | 1篇 |
1971年 | 1篇 |
1968年 | 1篇 |
1964年 | 1篇 |
1959年 | 1篇 |
1954年 | 1篇 |
1926年 | 1篇 |
1925年 | 1篇 |
1924年 | 1篇 |
1923年 | 1篇 |
1922年 | 1篇 |
排序方式: 共有153条查询结果,搜索用时 15 毫秒
51.
Power analysis as a reflexive scientific tool for interpretation and implementation of the precautionary principle in the European Union 总被引:1,自引:0,他引:1
Sanderson H Petersen S 《Environmental science and pollution research international》2002,9(4):221-226
The diversity of interpretation, the subsequent lack of implementation, and the enforcement of the precautionary principle have been important issues in the European environmental discourse for the past five years. The European Commission published a communication on the Commission's interpretation of the precautionary principle on February 2nd, 2000. However, the distinction between precaution and prevention is absent in the EU Commission's interpretation, resulting in the communication's lacking relevance for the precautionary principle. The important consequence of the precautionary concept in policy and decision-making is that it should not be based on an assumed certainty of the certainty of environmental knowledge--but rather on a certainty of the uncertainty of environmental knowledge. In other words, the regulation should, to a greater extent, be based on the management of uncertainty, and risk assessments should explicitly present and discuss related uncertainty and lack of knowledge. The management of uncertainty should be based on setting the acceptable level of risk of accepting a failure to reject the null hypothesis of no adverse effects (beta). This is done by setting the required power (1-beta) according to a socioeconomic cost-benefit analysis. Moreover, the acceptable ecological effect size (A) could also be set a priori which would have implications for the power of a study. Reversal of the burden of proof could be considered in order to resolve possible legal implications for the risk managers. 相似文献
52.
Petersen 《Die Naturwissenschaften》1922,10(17):439-440
53.
54.
Microbial growth and transport in porous media under denitrification conditions: experiments and simulations 总被引:1,自引:0,他引:1
T. P. Clement B. M. Peyton R. S. Skeen D. A. Jennings J. N. Petersen 《Journal of contaminant hydrology》1997,24(3-4)
Soil column experiments were conducted to study bacterial growth and transport in porous media under denitrifying conditions. The study used a denitrifying microbial consortium isolated from aquifer sediments sampled at the U.S. Department of Energy's Hanford site. One-dimensional, packed-column transport studies were conducted under two substrate loading conditions. A detailed numerical model was developed to predict the measured effluent cell and substrate concentration profiles. First-order attachment and detachment models described the interphase exchange processes between suspended and attached biomass. Insignificantly different detachment coefficient values of 0.32 and 0.43 day−1, respectively, were estimated for the high and low nitrate loading conditions (48 and 5 mg l−1 NO3, respectively). Comparison of these values with those calculated from published data for aerobically growing organisms shows that the denitrifying consortium had lower detachment rate coefficients. This suggests that, similar to detachment rates in reactor-grown biofilms, detachment in porous media may increase with microbial growth rate. However, available literature data are not sufficient to confirm a specific analytical model for predicting this growth dependence. 相似文献
55.
The reunification of Germany led to dramatically reduced emissions of nitrogen (N) and phosphorus (P) to the environment. The aim of the present study was to examine how these exceptional decreases influenced the amounts of nutrients carried by the Elbe River to the North Sea. In particular, we attempted to extract anthropogenic signals from time series of riverine loads of nitrogen and phosphorus by developing a normalization technique that enabled removal of natural fluctuations caused by several weather-dependent variables. This analysis revealed several notable downward trends. The normalized loads of total-N and NO3-N exhibited an almost linear trend, even though the nitrogen surplus in agriculture dropped dramatically in 1990 and then slowly increased. Furthermore, the decrease in total-P loads was found to be considerably smaller close to the mouth of the river than further upstream. Studying the predictive ability of different normalization models showed the following: (i) nutrient loads were influenced primarily by water discharge; (ii) models taking into account water temperature, load of suspended particulate matter, and salinity were superior for some combinations of sampling sites and nutrient species; semiparametric normalization models were almost invariably better than ordinary regression models. 相似文献
56.
An Object-Based Image Analysis of Pinyon and Juniper Woodlands Treated to Reduce Fuels 总被引:1,自引:0,他引:1
April Hulet Bruce A. Roundy Steven L. Petersen Ryan R. Jensen Stephen C. Bunting 《Environmental management》2014,53(3):660-671
Mechanical and prescribed fire treatments are commonly used to reduce fuel loads and maintain or restore sagebrush steppe rangelands across the Great Basin where pinyon (Pinus) and juniper (Juniperus) trees are encroaching and infilling. Geospatial technologies, particularly remote sensing, could potentially be used in these ecosystems to (1) evaluate the longevity of fuel reduction treatments, (2) provide data for planning and designing future fuel-reduction treatments, and (3) assess the spatial distribution of horizontal fuel structure following fuel-reduction treatments. High-spatial resolution color-infrared imagery (0.06-m pixels) was acquired for pinyon and juniper woodland plots where fuels were reduced by either prescribed fire, tree cutting, or mastication at five sites in Oregon, California, Nevada, and Utah. Imagery was taken with a Vexcel UltraCam X digital camera in June 2009. Within each treatment plot, ground cover was measured as part of the Sagebrush Steppe Treatment Evaluation Project. Trimble eCognition Developer was used to classify land cover classes using object-based image analysis (OBIA) techniques. Differences between cover estimates using OBIA and ground-measurements were not consistently higher or lower for any land cover class and when evaluated for individual sites, were within ±5 % of each other. The overall accuracy and the K hat statistic for classified thematic maps for each treatment were: prescribed burn 85 % and 0.81; cut and fell 82 % and 0.77, and mastication 84 % and 0.80. Although cover assessments from OBIA differed somewhat from ground measurements, they are sufficiently accurate to evaluate treatment success and for supporting a broad range of management concerns. 相似文献
57.
58.
Stefan Siebert Friederike Anton-Erxleben Rainer Kiko Maike Kramer 《Marine Biology》2009,156(4):541-554
Various cnidarians have adapted their life style to interstitial habitats of marine sediments. Recently, for the first time
a hydroid was reported from the interstitial brine channel system of Arctic fast ice. Due to its derived features, the new
genus and species Sympagohydra tuuli was introduced. Here we describe findings of S. tuuli in sea ice at several sites within the central Arctic Ocean. In our view the results of this study do not allow assignment
of Sympagohydra to any known family and we, therefore, suggest the introduction of a new family Sympagohydridae which is placed within the
hydrozoan subclass Hydroidolina, order Anthomedusae, suborder Capitata. A first detailed histological analysis of S. tuuli is presented. In vivo analysis of locomotion and reproduction revealed a remarkable convergent evolution in S. tuuli and distant meiobenthic relatives. Shared traits are a flagellated epidermis enabling the animals to glide within small interstices
by means of flagellar beating as well as an internalised embryogenesis. In S. tuuli gametogenesis occurs in the absence of gonophores inbetween gastro- and epidermis clearly separated from the epidermis. Budding
was observed as the vegetative mode of reproduction. Documentation of feeding behaviour identified copepod nauplii and rotifers
as prey items and demonstrates a high trophical position of the hydroids within the sympagic food web. Occurrence of reproducing
individuals and pronounced tolerances towards changing temperatures and salinities indicate S.
tuuli as a truly sympagic species.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
59.
60.
Examining Source-Receptor Relationships for Mercury in Scandinavia Modelled and Empirical Evidence 总被引:1,自引:0,他引:1
Munthe John Kindbom Karin Kruger Olaf Petersen Gerhard Pacyna Jozef Iverfeldt Åke 《Water, Air, & Soil Pollution: Focus》2001,1(3-4):299-310
The atmosphere remains the major source of mercuryin Swedish ecosystems. Since the late eighties,atmospheric emissions of mercury have drasticallydecreased in Europe. Wet deposition of mercury hasdecreased over the last decade but still exhibitsa clear south-to-north gradient, greatlyinfluenced by source areas in northern and centralEurope. The decreases in emissions can beattributed to both direct measures to close knownpoint sources and a declining economy and energyconsumption in many East European countries.Further reductions of mercury emissions willrequire that other source categories such asindirect emissions from mercury-containingproducts and crematories are be considered. 相似文献