全文获取类型
收费全文 | 593篇 |
免费 | 14篇 |
国内免费 | 7篇 |
专业分类
安全科学 | 18篇 |
废物处理 | 51篇 |
环保管理 | 76篇 |
综合类 | 48篇 |
基础理论 | 149篇 |
环境理论 | 1篇 |
污染及防治 | 201篇 |
评价与监测 | 42篇 |
社会与环境 | 11篇 |
灾害及防治 | 17篇 |
出版年
2022年 | 8篇 |
2021年 | 9篇 |
2020年 | 4篇 |
2019年 | 9篇 |
2018年 | 12篇 |
2017年 | 15篇 |
2016年 | 15篇 |
2015年 | 13篇 |
2014年 | 20篇 |
2013年 | 50篇 |
2012年 | 33篇 |
2011年 | 28篇 |
2010年 | 23篇 |
2009年 | 34篇 |
2008年 | 34篇 |
2007年 | 43篇 |
2006年 | 28篇 |
2005年 | 21篇 |
2004年 | 23篇 |
2003年 | 23篇 |
2002年 | 15篇 |
2001年 | 14篇 |
2000年 | 9篇 |
1999年 | 11篇 |
1998年 | 7篇 |
1997年 | 3篇 |
1996年 | 6篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 3篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1981年 | 2篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 3篇 |
1971年 | 3篇 |
1970年 | 4篇 |
1967年 | 3篇 |
排序方式: 共有614条查询结果,搜索用时 812 毫秒
611.
A general theory known as the waste reduction (WAR) algorithm has been developed to describe the flow and the generation of potential environmental impact through a chemical process. The theory defines indexes that characterize the generation and the output of potential environmental impact from a process. The existing theory has been extended to include the potential environmental impact of the energy consumed in a chemical process. Energy will have both an environmental impact as well as an economic impact on process design and analysis. Including energy into the analysis of environmental impact is done by re-writing the system boundaries to include the power plant which supplies the energy being consumed by the process and incorporating the environmental effects of the power plant into the analysis. The effect of this addition on the original potential impact indexes will be discussed. An extensive engineering economic evaluation has been included in the process analysis which inherently contains the cost of the consumed energy as an operating cost. A case study is presented which includes a base process design and two modifications to the base design. Each design is analyzed from an economic perspective and an environmental impact perspective. The environmental impact analysis is partitioned into the impacts of the non-product streams and the impacts of the energy generation/consumption process. The comparisons of these analysis procedures illustrate the consequences for decision making in the design of environmentally friendly processes. 相似文献
612.
Genetic Structure of Fragmented Populations of the Endangered Daisy Rutidosis leptorrhynchoides 总被引:2,自引:0,他引:2
Abstract: The endangered grassland daisy Rutidosis leptorrhynchoides has been subject to severe habitat destruction and fragmentation over the past century. Using allozyme markers, we examined the genetic diversity and structure of 16 fragmented populations. The species had high genetic variation compared to other plant species, and both polymorphism and allelic richness showed strong positive relationships with log reproductive population size, reflecting a loss of rare alleles (frequency of q < 0.1) in smaller populations. Fixation coefficients were positively related to size, due either to a lack of rare homozygotes in small populations or to Wahlund effects (owing to spatial genetic structure) in large ones. Neither gene diversity nor heterozygosity was related to population size, and other population parameters such as density, spatial contagion, and isolation had no apparent effect on genetic variation. Genetic divergence among populations was low , despite a large north-to-south break in the species' current distribution. To preserve maximum genetic variation, conservation strategies should aim to maintain the five populations larger than 5000 reproductive plants, all of which occur in the north of the range, as well as the largest southern population of 626 plants at Truganina. Only one of these is currently under formal protection. High heterozygosity in smaller populations suggests that they are unlikely to be suffering from inbreeding depression and so are also valuable for conservation. Erosion of allelic richness at self-incompatibility loci, however, may limit the reproductive capacity of populations numbering less than 20 flowering plants. 相似文献
613.
Lee Young Su Kim Young Kwon Choi Eunhwa Jo Hyeri Hyun Hyeseung Yi Seung-Muk Kim Jae Young 《Environmental science and pollution research international》2022,29(44):66591-66604
Environmental Science and Pollution Research - The emission sources and their health risks of fine particulate matter (PM2.5) in Siheung, Republic of Korea, were investigated as a middle-sized... 相似文献
614.
Hong Myung Hwan Joo So Young Kim Dong Wook Yoon Jin-Ho 《Journal of Material Cycles and Waste Management》2022,24(1):63-72
Journal of Material Cycles and Waste Management - Owing to the increasing ACW generation, asbestos detoxification and recycling technologies are required for environmental and economic reasons.... 相似文献