全文获取类型
收费全文 | 100篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 1篇 |
废物处理 | 2篇 |
环保管理 | 23篇 |
综合类 | 17篇 |
基础理论 | 20篇 |
污染及防治 | 26篇 |
评价与监测 | 7篇 |
社会与环境 | 5篇 |
灾害及防治 | 1篇 |
出版年
2023年 | 1篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 2篇 |
2014年 | 2篇 |
2013年 | 6篇 |
2012年 | 8篇 |
2011年 | 11篇 |
2010年 | 2篇 |
2009年 | 8篇 |
2008年 | 9篇 |
2007年 | 9篇 |
2006年 | 4篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2001年 | 1篇 |
1994年 | 2篇 |
1992年 | 1篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有102条查询结果,搜索用时 15 毫秒
61.
62.
63.
Arthur C. Miller Sonja N. Kerr Donald J. Spaeder 《Journal of the American Water Resources Association》1983,19(4):625-630
ABSTRACT Unit hydrograph theory is one of the most widely used techniques to predict surface runoff. The present study is concerned with the Snyder unit hydrograph and the calibration of the Snyder coefficients for Pennsylvania. Twenty-seven study basins were selected, located randomly across the state. With the rainfall and runoff recorded for several events for each basin (more than 500 events were analyzed) unit hydrographs were calculated and the Snyder coefficients determined. A map of the coefficients was drawn to illustrate the variability in the coefficients and two equations using multiple regression theory were developed. The unexplained variability of the coefficients suggests that upper and lower bounds on the peak flow might be placed on storm hydrographs developed for ungaged watersheds. 相似文献
64.
Jens Vandewijngaarden Ruben Wauters Marius Murariu Philippe Dubois Robert Carleer Jan Yperman Jan D’Haen Bart Ruttens Sonja Schreurs Nadia Lepot Roos Peeters Mieke Buntinx 《Journal of Polymers and the Environment》2016,24(2):104-118
Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) is a versatile, biobased and biodegradable copolymer from the family of polyhydroxyalkanoates. This study aims to further ameliorate its properties in order to enhance its applicability for food packaging purposes through preparation of organomodified montmorillonite clay (OMMT) nanocomposites. Nanocomposites based on pure PHBHHx as well as commercial PHBHHx granulate, after a previous dry-mixing with OMMT in concentrations of 1, 3, 5 and 10 wt%, were prepared using melt blending and compression molding. Investigation of the samples showed well dispersed nanofiller and highly intercalated nanocomposites, resulting in a continuous decrease in gas permeability, lowering O2, CO2 and water vapor permeability with about 5–7 % and approximately 40 % at OMMT concentration of 1 and 10 wt%, respectively. Besides gas permeability, other properties were affected as well. Thermal stability of the samples increased gradually up to 5 wt% nanofiller, but was reduced at 10 wt%. In order to investigate the effects of OMMT and molecular weights on PHBHHx crystallization, nanocomposites were also produced by solvent-casting and compared to those obtained by melt-blending. Crystallization was retarded, because of severe lowering of molecular weight due to processing-induced chain scission, catalyzed by OMMT moisture. However, this reduction was counteracted for a large part by using commercial PHBHHx granulate, which has shown better crystallization properties. The samples were rendered increasingly more brittle, displaying higher Young’s modulus and severely reduced elongation at break. From this study it appeared that, upon viewing all affected properties as a whole, the sample based on commercial PHBHHx and containing 3 wt% OMMT shows most promise for possible applications, however further research must be performed in order to exploit their fullest potential. 相似文献
65.
Sonja?LojenEmail author Ehud?Spanier Anat?Tsemel Timor?Katz Noa?Eden Dror?L.?Angel 《Marine Biology》2005,148(1):87-96
The flow of particulate nitrogen from marine net pen fish farm effluents to the surrounding biofouling community was quantified by means of stable isotopes of nitrogen. Plastic mesh substrates were deployed at 8 m depth near a sea bream fish farm and at a nearby reference site in the northern Gulf of Aqaba (Red Sea) to assess whether natural fouling organisms could sequester substantial quantities of farm-derived particulate nitrogen waste. A mixing equation, incorporating differences in nitrogen stable isotope composition, δ15N, between particulate organic matter (“source”) and fouling organisms (“sink”) at the fish farm and reference site, was used to estimate the amount of farm-derived nitrogen that was incorporated by the fouling community. Among the conspicuous fouling organisms examined, sponges, tunicates and polychaetes showed greatest uptake of fish farm N, where the mean fractions of farm-derived N estimated over the 2-year period of observation were 19±7, 22±6 and 31±8% of total organisms’ N content, respectively, with maximal recorded seasonal values of 68, 85 and 57%, respectively. Mean N uptake by mixed fouling communities (conspicuous + cryptic organisms) was as much as fivefold higher than that calculated for the sum of conspicuous taxa, suggesting that the retention efficiency is greater in mixed than in mono-specific biofouling communities. 相似文献
66.
The variability in surface water chemistry within and between aquatic ecosystems is regulated by many factors operating at
several spatial and temporal scales. The importance of geographic, regional-, and local-scale factors as drivers of the natural
variability of three water chemistry variables representing buffering capacity and the importance of weathering (acid neutralizing
capacity, ANC), nutrient concentration (total phosphorus, TP), and importance of allochthonous inputs (total organic carbon,
TOC) were studied in boreal streams and lakes using a method of variance decomposition. Partial redundancy analysis (pRDA)
of ANC, TP, and TOC and 38 environmental variables in 361 lakes and 390 streams showed the importance of the interaction between
geographic position and regional-scale variables. Geographic position and regional-scale factors combined explained 15.3%
(streams) and 10.6% (lakes) of the variation in ANC, TP, and TOC. The unique variance explained by geographic, regional, and
local-scale variables alone was <10%. The largest amount of variance was explained by the pure effect of regional-scale variables
(9.9% for streams and 7.8% for lakes), followed by local-scale variables (2.9% and 5.8%) and geographic position (1.8% and
3.7%). The combined effect of geographic position, regional-, and local-scale variables accounted for between 30.3% (lakes)
and 39.9% (streams) of the variance in surface water chemistry. These findings lend support to the conjecture that lakes and
streams are intimately linked to their catchments and have important implications regarding conservation and restoration (management)
endeavors. 相似文献
67.
Halstensen AS Nordby KC Eduard W Klemsdal SS 《Journal of environmental monitoring : JEM》2006,8(12):1235-1241
Inhalation of immunomodulating mycotoxins produced by Fusarium spp. that are commonly found in grain dust may imply health risks for grain farmers. Airborne Fusarium and mycotoxin exposure levels are mainly unknown due to difficulties in identifying Fusarium and mycotoxins in personal aerosol samples. We used a novel real-time PCR method to quantify the fungal trichodiene synthase gene (tri5) and DNA specific to F. langsethiae and F. avenaceum in airborne and settled grain dust, determined the personal inhalant exposure level to toxigenic Fusarium during various activities, and evaluated whether quantitative measurements of Fusarium-DNA could predict trichothecene levels in grain dust. Airborne Fusarium-DNA was detected in personal samples even from short tasks (10-60 min). The median Fusarium-DNA level was significantly higher in settled than in airborne grain dust (p < 0.001), and only the F. langsethiae-DNA levels correlated significantly in settled and airborne dust (r(s) = 0.20, p = 0.003). Both F. langsethiae-DNA and tri5-DNA were associated with HT-2 and T-2 toxins (r(s) = 0.24-0.71, p < 0.05 to p < 00.01) in settled dust, and could thus be suitable as indicators for HT-2 and T-2. The median personal inhalant exposure to specific toxigenic Fusarium spp. was less than 1 genome m(-3), but the exposure ranged from 0-10(5) genomes m(-3). This study is the first to apply real-time PCR on personal samples of inhalable grain dust for the quantification of tri5 and species-specific Fusarium-DNA, which may have potential for risk assessments of inhaled trichothecenes. 相似文献
68.
Boreal forests in Sweden are exploited in a number of ways, including forestry and reindeer husbandry. In the winter, reindeer
feed mainly on lichens, and lichen-rich forests are a key resource in the herding system. Commercial forestry has mainly negative
effects on reindeer husbandry, and conflicts between these two industries have escalated over the last century. This article
reviews the effects of modern forest management practices on the winter resources available for reindeer husbandry. Forestry
affects reindeer husbandry at both the stand level and the landscape level and over various time scales. Clear-cutting, site
preparation, fertilization, short rotation times, and forest fragmentation have largely resulted in a reduced amount of ground
growing and arboreal lichens and restricted access to resource. This article also discusses alternative forestry practices
and approaches that could reduce the impacts of forestry on reindeer husbandry, both in the short and long term. 相似文献
69.
Assessing the Cr(VI) reduction efficiency of a permeable reactive barrier using Cr isotope measurements and 2D reactive transport modeling 总被引:1,自引:0,他引:1
In Thun, Switzerland, a permeable reactive barrier (PRB) for Cr(VI) reduction by gray cast iron was installed in May 2008. The PRB is composed of a double array of vertical piles containing iron shavings and gravel. The aquifer in Thun is almost saturated with dissolved oxygen and the groundwater flow velocities are ca. 10-15m/day. Two years after PRB installation Cr(VI) concentrations still permanently exceed the Swiss threshold value for contaminated sites downstream of the barrier at selected localities. Groundwater δ(53/52)Cr(SRM979) measurements were used to track Cr(VI) reduction induced by the PRB. δ(53/52)Cr(SRM979) values of two samples downstream of the PRB showed a clear fractionation towards more positive values compared to four samples from the hotspot, which is clear evidence of Cr(VI) reduction induced by the PRB. Another downstream sample did not show a shift to more positive δ(53/52)Cr(SRM979) values. Because this latter location correlates with the highest downstream Cr(VI) concentration it is proposed that a part of the Cr(VI) plume is bypassing the barrier. Using a Rayleigh fractionation model a minimum present-day overall Cr(VI) reduction efficiency of ca. 15% was estimated. A series of 2D model simulations, including the fractionation of Cr isotopes, confirm that only a PRB bypass of parts of the Cr(VI) plume can lead to the observed values. Additionally, the simulations revealed that the proposed bypass occurs due to an insufficient permeability of the individual PRB piles. It is concluded that with this type of PRB a complete and long-lasting Cr(VI) reduction is extremely difficult to achieve for Cr(VI) contaminations located in nearly oxygen and calcium carbonate saturated aquifer in a regime of high groundwater velocities. Additional remediation action would limit the environmental impact and allow to reach target concentrations. 相似文献
70.
Kaisarevic S Hilscherova K Weber R Sundqvist KL Tysklind M Voncina E Bobic S Andric N Pogrmic-Majkic K Vojinovic-Miloradov M Giesy JP Kovacevic R 《Environmental science and pollution research international》2011,18(4):677-686