全文获取类型
收费全文 | 5051篇 |
免费 | 519篇 |
国内免费 | 1499篇 |
专业分类
安全科学 | 592篇 |
废物处理 | 207篇 |
环保管理 | 503篇 |
综合类 | 3276篇 |
基础理论 | 745篇 |
污染及防治 | 886篇 |
评价与监测 | 345篇 |
社会与环境 | 292篇 |
灾害及防治 | 223篇 |
出版年
2024年 | 28篇 |
2023年 | 90篇 |
2022年 | 247篇 |
2021年 | 215篇 |
2020年 | 280篇 |
2019年 | 198篇 |
2018年 | 215篇 |
2017年 | 248篇 |
2016年 | 247篇 |
2015年 | 285篇 |
2014年 | 336篇 |
2013年 | 453篇 |
2012年 | 443篇 |
2011年 | 509篇 |
2010年 | 437篇 |
2009年 | 436篇 |
2008年 | 384篇 |
2007年 | 400篇 |
2006年 | 361篇 |
2005年 | 253篇 |
2004年 | 194篇 |
2003年 | 155篇 |
2002年 | 143篇 |
2001年 | 124篇 |
2000年 | 107篇 |
1999年 | 61篇 |
1998年 | 43篇 |
1997年 | 36篇 |
1996年 | 32篇 |
1995年 | 21篇 |
1994年 | 23篇 |
1993年 | 17篇 |
1992年 | 18篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1964年 | 1篇 |
1961年 | 1篇 |
1958年 | 2篇 |
排序方式: 共有7069条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
对"地球表层概念"的界定与发展和基于新概念的地球表层系统(结构)等进行了综合讨论和阐述;定义了地球表层概念的内涵,提出:地球表层是指地表和近地表各圈层相互作用和渗透的地球部分,是地球上部多态(固、液、气、生物和有机态)物质相互渗透、交融并不断进行物能交换、转化和作用而结合形成的具有内部协同性和一定系统结构的有机整体,是地球生物的生存环境和地表生态系统发生、发展和演化的基础;进一步确立了地球表层的空间位置和范围(外延),即包括地球表面上下的岩石圈、水圈、大气圈、生物圈和物理(能量)场及其相关作用在内的地球空间,其下界是软流圈(以软流圈为过渡层),上界为大气圈最外层,至少应包括磁层在内;岩石圈以下的地幔和地核与大气圈以外的宇宙空间均为地球表层的环境. 相似文献
105.
106.
中国湿地现状综述 总被引:9,自引:0,他引:9
刘军 《中国环境管理干部学院学报》2004,14(2):64-67
湿地是重要的自然资源,对人类生存起着重要作用。本文综述了湿地的含义、功能与 价值、中国湿地的特点与现状,以促进中国湿地的可持续发展与利用。 相似文献
107.
本文分析了利用产业信托投资城市环境基础设施的可行性和现实性,并做出一个环境基础设施信托投资方案的结构设计。 相似文献
108.
Yongsung Cho K. William. Easter Laura M.J. McCann Frances Homans 《Journal of the American Water Resources Association》2005,41(3):729-740
ABSTRACT: The concentrations of iron and sulfate in community water supplies are a concern for a number of areas in southwestern Minnesota. This study used the contingent valuation method to determine how much consumers would be willing to pay to improve their drinking water quality. On average, individuals were willing to pay US$5.25 per month (in 1995 U.S. dollars) to reduce the level of iron and US$4.33 per month to reduce the level of sulfate in their water to the USEPA's secondary standards for drinking water quality. Respondents with negative perceptions of their drinking water quality were willing to pay more to improve water quality. The aggregate annual willingness to pay (WTP) for all consumers in community water systems in southwestern Minnesota that were out of compliance with water quality standards were estimated to be US$2.4 million and US$2.0 million (in 1995 dollars) for reducing the levels of iron and sulfate, respectively. Yet the total WTP of consumers who use small community water systems may not be enough to pay the full cost of providing improved water in those systems. Economies of scale in water treatment and difficulties in financing improvements mean that technical innovation, government assistance, or institutional changes may be needed to improve water quality in these areas. 相似文献
109.
Lin CJ Ho TC Chu HW Yang H Mojica MJ Krishnarajanagar N Chiou P Hopper JR 《Journal of environmental management》2005,75(4):303-313
Emission inventory is one of the required inputs to air quality models. To assist in the urban and regional modeling efforts, United States Environmental Protection Agency (EPA) has compiled a National Emission Inventory (NEI) for criterion pollutants, and the precursors of ozone and particulate matter (PM). In December 2002, EPA released the 1999 NEI estimates (NEI99), which represent the most recent national emission data. However, the data sets are not in model-ready format for air quality simulations. This present work converts the NEI99 Final Version 2 data sets into Inventory Data Analyzer (IDA) format and processes the data using the Sparse Matrix Operator Kernel Emissions (SMOKE) modeling system to generate a gridded emission inventory in a domain covering the west Gulf Coast Region, USA. The spatial and diurnal emission characteristics of the gridded emission inventories are then assessed and compared with those of the National Emission Trend 1996 (NET96). The NEI99 database contains more complete emission records in both area and point sources. It is also found that NEI99 data exhibit greater emissions with respect to point and mobile sources but smaller emissions with respect to area sources when compared to the corresponding gridded NET96 data in the same study domain. The most distinct differences between the NEI99 and NET96 databases are CO emission of mobile sources, SO2 emissions of point sources, and VOC/PM/NH3/NOx emissions of area and non-road sources. The gridded NEI99 data show low VOC/NOx ratios (<2-5) in the urban areas of the study domain. 相似文献
110.