全文获取类型
收费全文 | 612篇 |
免费 | 19篇 |
国内免费 | 5篇 |
专业分类
安全科学 | 14篇 |
废物处理 | 33篇 |
环保管理 | 98篇 |
综合类 | 70篇 |
基础理论 | 188篇 |
污染及防治 | 161篇 |
评价与监测 | 46篇 |
社会与环境 | 22篇 |
灾害及防治 | 4篇 |
出版年
2023年 | 6篇 |
2022年 | 6篇 |
2021年 | 7篇 |
2020年 | 7篇 |
2019年 | 8篇 |
2018年 | 14篇 |
2017年 | 26篇 |
2016年 | 25篇 |
2015年 | 17篇 |
2014年 | 14篇 |
2013年 | 66篇 |
2012年 | 15篇 |
2011年 | 24篇 |
2010年 | 16篇 |
2009年 | 25篇 |
2008年 | 34篇 |
2007年 | 36篇 |
2006年 | 18篇 |
2005年 | 22篇 |
2004年 | 22篇 |
2003年 | 15篇 |
2002年 | 15篇 |
2001年 | 19篇 |
2000年 | 11篇 |
1999年 | 8篇 |
1998年 | 6篇 |
1997年 | 8篇 |
1996年 | 11篇 |
1995年 | 10篇 |
1994年 | 12篇 |
1993年 | 8篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 7篇 |
1989年 | 5篇 |
1988年 | 10篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 8篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1973年 | 3篇 |
1972年 | 5篇 |
1969年 | 4篇 |
排序方式: 共有636条查询结果,搜索用时 593 毫秒
321.
Corruption, political competition and environmental policy 总被引:2,自引:0,他引:2
John K. Wilson Richard Damania 《Journal of Environmental Economics and Management》2005,49(3):516-535
This paper examines the interplay between corruption, political competition, environmental policy and environmental outcomes. An important feature of the model, which has been neglected in the existing literature, is that corruption may occur at different levels of government, such as the payment of bribes to politicians who determine policies, or bureaucrats who administer environmental regulations. We analyse the relationship between political competition and environmental outcomes in a model of stratified corruption and identify the benefits and limits of political competition. Our results suggest that while political competition may yield policy improvements, it cannot eliminate corruption at all levels of government. 相似文献
322.
323.
Christian A. Chisholm Fotini Vavelidis Mark A. Lovell Lawrence Sweetman Charles R. Roe Diane S. Roe Frank E. Frerman William G. Wilson 《黑龙江环境通报》2001,21(10):856-859
We report the occurrence of multiple acyl-CoA dehydrogenase deficiency (MADD) in two consecutive pregnancies in a young, Caucasian, non-consanguineous couple. In the first pregnancy, the maternal serum α-fetoprotein was elevated. A sonogram showed growth delay, cystic renal disease, and oligohydramnios; the parents decided to terminate the pregnancy. Postmortem examination confirmed the cystic renal disease and showed hepatic steatosis, raising the suspicion of a metabolic disorder. The diagnosis of MADD was made by immunoblot studies on cultured fibroblasts. In the subsequent pregnancy, a sonogram at 15 weeks' gestation showed an early growth delay but normal kidneys. The maternal serum and amniotic fluid concentrations of α-fetoprotein were elevated, and the amniotic fluid acylcarnitine profile was consistent with MADD. In vitro metabolic studies on cultured amniocytes confirmed the diagnosis. A follow-up sonogram showed cystic renal changes. These cases provide additional information regarding the evolution of renal changes in affected fetuses and show a relationship with elevated α-fetoprotein, which may be useful in counseling the couple at risk. MADD should be considered in the differential diagnosis of elevated α-fetoprotein and cystic renal disease. Early growth delay may be an additional feature. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
324.
325.
Minke E. Newman Kurt P. McLaren Byron S. Wilson 《Environmental monitoring and assessment》2011,172(1-4):391-406
Forest fragmentation is one of the most important threats to global biodiversity, particularly in tropical developing countries. Identifying priority areas for conservation within these forests is essential to their effective management. However, this requires current, accurate environmental information that is often lacking in developing countries. The Cockpit Country, Jamaica, contains forests of international importance in terms of levels of endemism and overall diversity. These forests are under severe threat from the prospect of bauxite mining and other anthropogenic disturbances. In the absence of adequate, up-to-date ecological information, we used satellite remote sensing data and fragmentation analysis to identify interior forested areas that have experienced little or no change as priority conservation sites. We classified Landsat images from 1985, 1989, 1995, 2002, and 2008, using an object-oriented method, which allowed for the inclusion of roads. We conducted our fragmentation analysis using metrics to quantify changes in forest patch number, area, shape, and aggregation. Deforestation and fragmentation fluctuated within the 23-year period but were mostly confined to the periphery of the forest, close to roads and access trails. An area of core forest that remained intact over the period of study was identified within the largest forest patch, most of which was located within the boundaries of a forest reserve and included the last remaining patches of closed-broadleaf forest. These areas should be given highest priority for conservation, as they constitute important refuges for endemic or threatened biodiversity. Minimizing and controlling access will be important in maintaining this core. 相似文献
326.
327.
An experiment to investigate how the water quality of acid lakes can be improved by liming the surrounding catchment was begun at Loch Fleet, Scotland in 1984. the effects on the soils of three sectors of the catchment where limestone was added in 1986 are reported here, following analysis of soils sampled in 1987, 1988 and 1991. the effect of the lime on soil chemistry was still evident in 1991, with about 15% of free lime remaining in the hydrochemical reaction zone of sectors IV and VI and nearly 50% in sector VII. However, this free lime appeared to be dissolving too slowly to maintain large amounts of exchangeable calcium in the soils, indicating that the treatment is starting to become less effective. the fall in the mean exchangeable calcium in the reaction zone between 1988 and 1991 was mirrored by a drop in mean soil pH over the 5 years post-liming from 6.1 to 5.6 on sector IV and from 5.9 to 5.4 on sector VI, whereas mean pH remained constant at about 6.0 in the limed areas of sector VII. Using soil data to predict longevity suggests that the exchangeable calcium remaining on the catchment at the end of 1991 will maintain target water quality in the loch until sometime during 1994. the soil pH is likely to fall to between 5.2 and 5.3 by this time. If the region of hydrochemical reaction is assumed to extend to a depth of 20 cm rather than 5 cm, target water quality is predicted to be maintained until the end of 1995. When the free lime remaining on the catchment is included as a source of acid neutralising capacity, calculations show that treatment may remain effective until around the year 2000. 相似文献
328.
329.
Various digestion or extraction processes are available for the determination of trace metals in environmental samples using diverse analytical techniques. Our research examines the most efficient and reproducible methods of digestion utilising readily available laboratory equipment, reagents and instrumentation. Extraction procedures reported in over 80 recent research works were considered and the most common methods were critically evaluated. Thus nitric acid, nitric acid/perchloric acid, aqua regia, nitric acid/hydrogen peroxide and microwave-assisted methods were investigated using soil and leaf samples collected adjacent to three old metalliferous workings. Analysis was carried out using Flame Atomic Absorption Spectrometry and the results were evaluated. Differences in efficiency of extraction relative to specific metals and different substrates are highlighted and recommendations made for a digestion procedure suitable for environmental samples. Aqua regia produced the most accurate, efficient and reproducible results; we consider methods of improving both of these factors and sample preparation. Our recommended methodology has applications in environmental surveys, environmental geology, environmental toxicology, geochemistry and provides a means of obtaining meaningful and reliable results for the determination of metals present in soils, minerals and vegetation. 相似文献
330.
Darío Fernández-Bellon Mark W. Wilson Sandra Irwin John O'Halloran 《Conservation biology》2019,33(2):413-422
Wind energy development is the most recent of many pressures on upland bird communities and their habitats. Studies of birds in relation to wind energy development have focused on effects of direct mortality, but the importance of indirect effects (e.g., displacement, habitat loss) on avian community diversity and stability is increasingly being recognized. We used a control-impact study in combination with a gradient design to assess the effects of wind farms on upland bird densities and on bird species grouped by habitat association (forest and open-habitat species). We conducted 506 point count surveys at 12 wind-farm and 12 control sites in Ireland during 2 breeding seasons (2012 and 2013). Total bird densities were lower at wind farms than at control sites, and the greatest differences occurred close to turbines. Densities of forest species were significantly lower within 100 m of turbines than at greater distances, and this difference was mediated by habitat modifications associated with wind-farm development. In particular, reductions in forest cover adjacent to turbines was linked to the observed decrease in densities of forest species. Open-habitat species’ densities were lower at wind farms but were not related to distance from turbines and were negatively related to size of the wind farm. This suggests that, for these species, wind-farm effects may occur at a landscape scale. Our findings indicate that the scale and intensity of the displacement effects of wind farms on upland birds depends on bird species’ habitat associations and that the observed effects are mediated by changes in land use associated with wind-farm construction. This highlights the importance of construction effects and siting of turbines, tracks, and other infrastructure in understanding the impacts of wind farms on biodiversity. 相似文献