全文获取类型
收费全文 | 120篇 |
免费 | 1篇 |
专业分类
安全科学 | 8篇 |
废物处理 | 3篇 |
环保管理 | 32篇 |
综合类 | 9篇 |
基础理论 | 30篇 |
环境理论 | 1篇 |
污染及防治 | 20篇 |
评价与监测 | 13篇 |
社会与环境 | 2篇 |
灾害及防治 | 3篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2020年 | 2篇 |
2019年 | 5篇 |
2017年 | 1篇 |
2016年 | 5篇 |
2015年 | 2篇 |
2014年 | 3篇 |
2013年 | 16篇 |
2012年 | 3篇 |
2011年 | 3篇 |
2010年 | 3篇 |
2009年 | 4篇 |
2008年 | 8篇 |
2007年 | 6篇 |
2006年 | 8篇 |
2005年 | 1篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2001年 | 2篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1992年 | 5篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1976年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有121条查询结果,搜索用时 15 毫秒
111.
D. A. Fraser M. C. Battigelli H. M. Cole 《Journal of the Air & Waste Management Association (1995)》2013,63(12):821-823
While the ciliary activity in the airways of rats exposed to sulfur dioxide at low concentration has been studied repeatedly, the effects of chronic exposure to realistic levels of sulfur dioxide and particulates has not been determined. This paper describes the response of white albino rats to the inhalation of low concentrations of sulfur dioxide while exposed to relatively high concentrations of an inert dust. Test results indicate that no change is found in the ciliary activity or the relative number of dust cells in the alveolar structure of rats exposed to 1 ppm of sulfur dioxide and 1 mg/m3 of a graphite dust. 相似文献
112.
Custer TW Dummer PM Custer CM Li AU Warburton D Melancon MJ Hoffman DJ Matson CW Bickham JW 《Environmental monitoring and assessment》2007,133(1-3):335-345
The U.S. Army Corps of Engineers conducted a water drawdown on Navigation Pool 8 of the Upper Mississippi River during the
summers of 2001 and 2002 to increase aquatic vegetation production and thereby improve fish and wildlife habitat. Flooding
of previously dried wetlands, however, may increase the rate of mercury methylation and make mercury more available to terrestrial
vertebrates that feed in aquatic environments. Our objective was to determine if mercury, other elements, and organochlorine
contaminants were more available to vertebrates following the 2001 drawdown. Tree swallow (Tachycineta bicolor) eggs and nestlings were collected at two sites on Pool 8 and a nearby Reference site in 2000 (pre-2001 drawdown), 2001 (pre-2001
drawdown) and 2002 (post-2001 drawdown) and tissues were analyzed for mercury, other elements, and organochlorine contaminants.
Bioindicator measurements of genetic damage, oxidative stress, ethoxyresorufin-O-dealkylase activity, and the ratio of liver to nestling mass were also measured in nestlings at all sites and all years.
Based on a multivariate analysis, the 2001 drawdown of Pool 8 did not influence element concentrations, organochlorine concentrations,
or bioindicator response. Concentrations of inorganic and organochlorine contaminants in tree swallow eggs and nestlings were
not at toxic levels. Hatching success did not differ among years and was comparable to the nationwide average. 相似文献
113.
114.
115.
Section 404 wetland mitigation and permit success criteria in Pennsylvania,USA, 1986-1999 总被引:2,自引:1,他引:1
Twenty-three Section 404 permits in central Pennsylvania (covering a wetland age range of 1–14 years) were examined to determine
the type of mitigation wetland permitted, how the sites were built, and what success criteria were used for evaluation. Most
permits allowed for mitigation out-of-kind, either vegetatively or through hydrogeomorphic class. The mitigation process has
resulted in a shift from impacted wetlands dominated by woody species to less vegetated mitigation wetlands, a trend that
appears to be occurring nationwide. An estimate of the percent cover of emergent vegetation was the only success criterion
specified in the majority of permits. About 60% of the mitigation wetlands were judged as meeting their originally defined
success criteria, some after more than 10 years. The permit process appears to have resulted in a net gain of almost 0.05
ha of wetlands per mitigation project. However, due to the replacement of emergent, scrub–shrub, and forested wetlands with
open water ponds or uplands, mitigation practices probably led to a net loss of vegetated wetlands. 相似文献
116.
Spatial patterns of recreation impact on experimental campsites 总被引:6,自引:0,他引:6
Management of camping impacts in protected areas worldwide is limited by inadequate understanding of spatial patterns of impact and attention to spatial management strategies. Spatial patterns of campsite impact were studied in two subalpine plant communities in the Wind River Mountains, Wyoming, USA (a forest and a meadow). Response to chronic disturbance and recovery from acute disturbance were both assessed. Previously undisturbed sites were camped on at intensities of one and four nights/year, for either one or three consecutive years. Recovery was followed for three years on sites camped on for one year. Percent bare ground, assessed in 49 contiguous 1 m2 quadrats, increased with increasing use frequency, particularly on the forest sites. Magnitude of impact varied spatially within campsites, with impact decreasing as distance from the center of the campsite increased. On the more fragile forest sites, this radial impact pattern developed rapidly and remained after three years of recovery. Concentration of camping activities around a centrally located small cooking stove was the apparent cause of this pattern. Maximum variation in magnitude of impact occurred at intermediate levels of campsite use and disturbance. The magnitude, variability and spatial pattern of impact varied with the spatial scale of analysis. Generally, results of these controlled experiments are consistent with earlier studies of campsites and validate the management implications derived from those studies. Even where campers use low-impact techniques, low levels of camping use can cause substantial impact and it is important to concentrate use. On resistant sites, however, it is possible that low levels of use can be sustained with minimal resultant impact. 相似文献
117.
118.
119.
In this study we explore whether emotion experienced at work mediates the relationships between perceived supervisor support, psychological hardiness, and employee cynicism. Data were collected from employees working at a medical technology company located in Switzerland. Mediational analyses showed that employees' positive and negative emotions experienced amidst an organizational crisis fully accounted for the relations between perceived supervisor support and cynicism and psychological hardiness and cynicism. Practical implications and directions for future research are discussed. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
120.
Campsite impact on three western Wilderness areas 总被引:1,自引:0,他引:1
Campsites were studied in subalpine forests in the Eagle Cap Wilderness in Oregon, and in the Mission Mountains Tribal Wilderness and the Rattlesnake Wilderness in Montana. Research objectives were to examine ecological changes on these sites and the extent to which these changes become more pronounced as use increases For most parameters measured, impact on campsites used for only a few nights per year exceeds threshold values beyond which further increases in use have little effect Loss of litter, tree root exposure, and site enlargement are the major types of alteration that are more pronounced on sites occupied more frequently than several nights per year In heavily used parts of backcountry areas, this suggests that ecological change can be minimized by limiting use to a small number of sites In the three areas studied, campsite occupancy rates would probably have to be no higher than a few nights per year before dispersal of use among a large number of sites would be an ecologically sound strategy 相似文献