全文获取类型
收费全文 | 1056篇 |
免费 | 21篇 |
国内免费 | 13篇 |
专业分类
安全科学 | 46篇 |
废物处理 | 35篇 |
环保管理 | 253篇 |
综合类 | 140篇 |
基础理论 | 271篇 |
环境理论 | 3篇 |
污染及防治 | 222篇 |
评价与监测 | 73篇 |
社会与环境 | 32篇 |
灾害及防治 | 15篇 |
出版年
2023年 | 10篇 |
2022年 | 11篇 |
2021年 | 12篇 |
2020年 | 21篇 |
2019年 | 15篇 |
2018年 | 22篇 |
2017年 | 25篇 |
2016年 | 29篇 |
2015年 | 23篇 |
2014年 | 33篇 |
2013年 | 100篇 |
2012年 | 40篇 |
2011年 | 70篇 |
2010年 | 38篇 |
2009年 | 45篇 |
2008年 | 55篇 |
2007年 | 83篇 |
2006年 | 42篇 |
2005年 | 37篇 |
2004年 | 29篇 |
2003年 | 34篇 |
2002年 | 36篇 |
2001年 | 28篇 |
2000年 | 18篇 |
1999年 | 13篇 |
1998年 | 14篇 |
1997年 | 14篇 |
1996年 | 15篇 |
1995年 | 8篇 |
1994年 | 14篇 |
1993年 | 13篇 |
1992年 | 7篇 |
1991年 | 6篇 |
1990年 | 10篇 |
1989年 | 12篇 |
1988年 | 6篇 |
1987年 | 10篇 |
1986年 | 5篇 |
1985年 | 6篇 |
1984年 | 8篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 12篇 |
1980年 | 5篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1975年 | 8篇 |
1974年 | 5篇 |
1972年 | 3篇 |
排序方式: 共有1090条查询结果,搜索用时 390 毫秒
81.
C. Annette Johnson Grald A. Richner Tomas Vitvar Nina Schittli Mark Eberhard 《Journal of contaminant hydrology》1998,33(3-4)
The objective of the investigation of the municipal solid waste incinerator (MSWI) bottom ash landfill, Landfill Lostorf, was to determine the residence time of water in the landfill and the flow paths through the landfill. Over a period of 22 months, measurements of rainfall, landfill discharge and leachate electrical conductivity were recorded and tracer experiments made. Over the yearly period 1995, approximately 50% of the incident rainfall was measured in the discharge. An analysis of single rain events showed that in winter, 90–100% of rainfall was expressed in the landfill discharge, whereas in summer months, the value was between 9 and 40% depending on the intensity of the rain event. The response to rainfall was rapid. Within 30–100 h, approximately 50% of water discharged in response to a rain event had left the landfill. The discharge was less than 4 l/min for approximately 50% of the measurement periods. Qualitative tracer studies with fluorescein, pyranine and iodide clearly showed the existence of preferential flow paths. This was further substantiated by quantitative tracer studies of single rain events using
/
ratios and electrical conductivity measurements. The proportion of rainwater passing directly through the landfill was found to be between 20 and 80% in summer months and around 10% in winter months. The difference has been ascribed to the water content in the landfill. The average residence time of the water within the landfill has been estimated to be roughly 3 years and this water is the predominant component in the discharge over a yearly period. 相似文献
82.
83.
84.
85.
Christopher J. Yahnke Warren E. Johnson Eli Geffen Deborah Smith Fritz Hertel Michael S. Roy Cristian F. Bonacic Todd K. Fuller Blaire Van Valkenburgh Robert K. Wayne 《Conservation biology》1996,10(2):366-375
The temperate rain forest of Chiloé Island, Chile, is inhabited by an endemic fox ( Dusicyon fulvipes ) first described by Charles Darwin and now designated Darwin's fox. Despite morphological differences, Darwin's fox has been considered only an insular subspecies of the mainland chilla fox ( D. griseus ). This follows the assumption that the island population, with an estimated population of less than 500, has been separated from the mainland chilla fox for only about 15,000 years and may have received occasional immigrants from the mainland. Consequently, this island population has not been protected as endangered or bred in captivity. Recently, a population of Darwin's fox was discovered on the Chilean mainland 600 km north of Chiloé Island. This population exists in sympatry with chilla and possibly culpeo ( D. culpaeus ) foxes, which suggests that Darwin's fox may be reproductively isolated. To clarify the phylogenetic position of Darwin's fox, we analyzed 344 bp of mitochondrial DNA control-region sequence of the three species of Chilean foxes. Darwin's foxes from the island and mainland populations compose a monophyletic group distinct from the two other Chilean fox species. This indicates that Darwin's fox was probably an early inhabitant of central Chile, and that its present distribution on the mainland may be a relict of a once much wider distribution. Our results highlight the ability of molecular genetic techniques to uncover historical relationships masked by recent events, such as local extinctions. The "rediscovery" of Darwin's fox as a distinct species implies that greater significance should be given to the protection of this species and its unique habitat and to documenting the extent of its mainland distribution. 相似文献
86.
87.
The Las Vegas Wash is an excavated waterway channel which drains all surface water and effluent discharge from sewage-treatment facilitates from the greater Las Vegas Metropolitan Area to Lake Mead. Fine and course sediment samples were collected at 100-m intervals and analyzed to determine the distribution of gamma-emitting radionuclides in the lower 5,500 m of the Las Vegas Wash. Results indicate depletion of long-lived fission products in upstream Wash sediments. However, trace levels of 137Cs measured in downstream sediments suggest the resuspension and transport of radioactive fallout within the Wash. Levels of 40K, 232Th, 235U, and 238U found in Wash sediments were consistent with levels typically found in southeast Nevada soils. 相似文献
88.
89.
90.