全文获取类型
收费全文 | 281篇 |
免费 | 6篇 |
专业分类
安全科学 | 13篇 |
废物处理 | 16篇 |
环保管理 | 59篇 |
综合类 | 37篇 |
基础理论 | 72篇 |
污染及防治 | 51篇 |
评价与监测 | 27篇 |
社会与环境 | 8篇 |
灾害及防治 | 4篇 |
出版年
2023年 | 3篇 |
2022年 | 7篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 4篇 |
2017年 | 8篇 |
2016年 | 8篇 |
2015年 | 10篇 |
2014年 | 14篇 |
2013年 | 20篇 |
2012年 | 10篇 |
2011年 | 22篇 |
2010年 | 6篇 |
2009年 | 10篇 |
2008年 | 17篇 |
2007年 | 13篇 |
2006年 | 9篇 |
2005年 | 10篇 |
2004年 | 4篇 |
2003年 | 8篇 |
2002年 | 11篇 |
2001年 | 5篇 |
2000年 | 6篇 |
1999年 | 8篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 6篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 6篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1970年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有287条查询结果,搜索用时 15 毫秒
231.
Key Elements of Landscape Pattern Measures 总被引:9,自引:0,他引:9
232.
Hans Schreier Sandra Brown Margaret Schmidt Pravakar Shah Bubhan Shrestha Gopal Nakarmi Khagendra Subba Susanne Wymann 《Environmental management》1994,18(1):139-150
GIS overlay techniques were used to provide a quantitative historic documentation of deforestation and land-use dynamics in
the Middle Mountains of Nepal between 1947 and 1990. Deforestation was most critical in the 1960s, but active afforestation
programs in the 1980s have reversed the process. In spite of these trends, the degradation problem is more complex. The GIS
evaluation showed that 86% of the recently afforested land is now under pine plantations located primarily at lower elevations
and moderately steep slopes. In contrast, rainfed agricultural expansion is most pronounced on acidic soils and steeper, upper
elevation sites, suggesting marginalization of agriculture. Agricultural expansion coupled with major losses of grazing land
to pine forests are the key processes pointing towards major animal feed deficits. An alternative animal feed source is suggested
through GIS using a topographically based microclimatic classification to generate a tree-planting map where the optimum ecological
conditions for selective native fodder tree species are identified. 相似文献
233.
Conservation and the Social Sciences 总被引:16,自引:0,他引:16
234.
235.
Emily Mann Michael A. Long Paul B. Stretesky Margaret Anne Defeyter 《Local Environment》2018,23(10):1008-1022
In response to the problem of holiday hunger, hundreds of local “holiday clubs” have recently been established across the UK. This research examines the spatial relationship between income, childhood deprivation, ethnicity and holiday clubs across 32,844 Lower Super Output Areas (LSOAs) in England to determine if these clubs are currently operating in an inclusive fashion. Data on the location of holiday clubs comes from a national survey. Binary logistic regression results suggest that holiday clubs are likely to operate in economically disadvantaged areas. At the same time, clubs are not distributed equally by ethnicity. That is, holiday clubs operated by voluntary organisations are more likely to be situated in LSOAs that are disproportionately white and English\British and less likely to be situated in LSOAs that are disproportionately ethnic minority. This finding has important implications for the pursuit of holiday clubs as a policy mechanism for addressing access to food in light of the state’s failure to adequately feed all of the country’s children. 相似文献
236.
237.
Spatial Optimization of Six Conservation Practices Using Swat in Tile‐Drained Agricultural Watersheds 下载免费PDF全文
Margaret M. Kalcic Jane Frankenberger Indrajeet Chaubey 《Journal of the American Water Resources Association》2015,51(4):956-972
Targeting of agricultural conservation practices to the most effective locations in a watershed can promote wise use of conservation funds to protect surface waters from agricultural nonpoint source pollution. A spatial optimization procedure using the Soil and Water Assessment Tool was used to target six widely used conservation practices, namely no‐tillage, cereal rye cover crops (CC), filter strips (FS), grassed waterways (GW), created wetlands, and restored prairie habitats, in two west‐central Indiana watersheds. These watersheds were small, fairly flat, extensively agricultural, and heavily subsurface tile‐drained. The targeting approach was also used to evaluate the model's representation of conservation practices in cost and water quality improvement, defined as export of total nitrogen, total phosphorus, and sediment from cropped fields. FS, GW, and habitats were the most effective at improving water quality, while CC and wetlands made the greatest water quality improvement in lands with multiple existing conservation practices. Spatial optimization resulted in similar cost‐environmental benefit tradeoff curves for each watershed, with the greatest possible water quality improvement being a reduction in total pollutant loads by approximately 60%, with nitrogen reduced by 20‐30%, phosphorus by 70%, and sediment by 80‐90%. 相似文献
238.
Margaret E. M. Tolbert Johnson A. Kamalu Garnette D. Draper 《Journal of environmental science and health. Part. B》2013,48(5):575-585
Abstract The effects of divalent cations on gluconeogenesis in enzy‐matically isolated rat hepatic parenchymal cells were examined. Cadmium, zinc and copper decreased glucose production from lactate (10 mM). However, manganese at 0.05 to 1.0 mM levels stimulated gluconeogenesis by the cells and reduced the effects of the Cd+2, Zn+2 and Cu+2 on gluconeogenesis. The results indicate that under these in vitro conditions the cations altered an aspect of hepatic function—gluconeogenesis from lactate. 相似文献
239.
240.
Margaret B. Williams Rebecca R.H. Michelsen Jessica L. Axson Laura T. Iraci 《Atmospheric environment (Oxford, England : 1994)》2010,44(9):1145-1151
The solubilities of acetone, ethanol and acetaldehyde in cold ternary solutions composed of 38.4–75.0 wt% sulfuric acid in water with additional dissolved organic material have been measured over the temperature range 214.4–238.5 K using a Knudsen cell reactor. The solubility of acetaldehyde in H2SO4/H2O is enhanced by an order of magnitude by the presence of ethanol or acetone. The reactive uptake of acetaldehyde is enhanced by the presence of formaldehyde in acid solution. No significant formation of acetals from ethanol with carbonyl partners was observed. The solubility of acetone is unaffected by the presence of ethanol in solution and vice versa. Only polymerization of small aldehydes offers a potentially significant route to the accretion of organic material into acidic particles in the upper troposphere. The acid-catalyzed polymerization of aldehydes, RC(H)O + R′C(H)O, proceeds through the hydrated forms of the aldehydes, is optimized at acidities around 40 wt% H2SO4, and can potentially accumulate significant amounts (>20%) of organic material by mass in upper tropospheric particles. 相似文献