全文获取类型
收费全文 | 1942篇 |
免费 | 186篇 |
国内免费 | 8篇 |
专业分类
安全科学 | 116篇 |
废物处理 | 123篇 |
环保管理 | 345篇 |
综合类 | 685篇 |
基础理论 | 476篇 |
污染及防治 | 270篇 |
评价与监测 | 42篇 |
社会与环境 | 22篇 |
灾害及防治 | 57篇 |
出版年
2020年 | 11篇 |
2019年 | 39篇 |
2018年 | 64篇 |
2017年 | 52篇 |
2016年 | 59篇 |
2015年 | 58篇 |
2014年 | 67篇 |
2013年 | 256篇 |
2012年 | 65篇 |
2011年 | 78篇 |
2010年 | 75篇 |
2009年 | 61篇 |
2008年 | 62篇 |
2007年 | 55篇 |
2006年 | 60篇 |
2005年 | 54篇 |
2004年 | 64篇 |
2003年 | 58篇 |
2002年 | 60篇 |
2001年 | 33篇 |
2000年 | 32篇 |
1999年 | 16篇 |
1998年 | 14篇 |
1995年 | 14篇 |
1994年 | 19篇 |
1993年 | 11篇 |
1978年 | 10篇 |
1966年 | 11篇 |
1965年 | 15篇 |
1964年 | 15篇 |
1963年 | 25篇 |
1962年 | 17篇 |
1961年 | 14篇 |
1960年 | 23篇 |
1959年 | 24篇 |
1958年 | 15篇 |
1957年 | 16篇 |
1956年 | 15篇 |
1955年 | 27篇 |
1954年 | 34篇 |
1953年 | 19篇 |
1952年 | 14篇 |
1951年 | 24篇 |
1947年 | 11篇 |
1939年 | 9篇 |
1938年 | 12篇 |
1933年 | 9篇 |
1931年 | 11篇 |
1930年 | 12篇 |
1929年 | 13篇 |
排序方式: 共有2136条查询结果,搜索用时 31 毫秒
11.
Salam A Bauer H Kassin K Ullah SM Puxbaum H 《Journal of environmental monitoring : JEM》2003,5(3):483-490
Aerosol constituents (elemental carbon, organic carbon, soluble ions including organic acids, and selected trace metals) were investigated from samples of a field campaign taking place at Bhola Island in the Bay of Bengal (Bangladesh). The campaign took place in the pre-monsoon season (May 2001) using low volume samplers. Carbonaceous material comprised the majority of the analysed components. The average concentrations of EC and OC were 2.8 and 4.6 microg m(-3), respectively. Oxalic acid was the most abundant dicarboxylic acid (average 268 ng m(-3)) followed by malonic and malic acid. The contribution of carboxylic acids-carbon to organic carbon was 2.0%. Average concentrations observed for sulfate and nitrate were 3.7 microg m(-3) and 1.5 microg m(-3). Two different types of aerosol were identified at the rural background site on Bhola Island during southerly synoptic flow by means of trajectory analysis: air masses were transported from the Bay of Bengal to the sampling site in all cases. However, during "Period 1" they experienced longer residence times over the Indian Ocean, while the "Period 2" trajectories came along the Indian coast or passed over the Indian continent. During Period 1 the concentration levels of soluble ions were a factor of 4-6 lower than during Period 2. The concentrations of EC, OC and K differed less than a factor of 1.5 between the two periods. The Period 1 aerosol showed similarities to the haze layers observed during winter-monsoon conditions south of India during the INDOEX experiment. Based on EC/TC and K/EC ratios we find that around 80% of the carbonaceous aerosol from Period 1 in Bhola is from fossil fuel and only around 50% from Period 2. Absolute concentrations of carbonaceous species, soluble ions and trace metals indicate that the background site on Bhola Island is affected by emissions from urbanized regions of Southeast Asia. 相似文献
12.
K. G. Willis Malcolm Newson Sonja Boehmer‐Christiansen 《Journal of Environmental Planning and Management》1994,37(2):243-247
Cost Benefit Analysis of Environmental Change
Per‐Olov Johansson
Cambridge, Cambridge University Press, 1993, 232 pp., £13.95
Computerised Environmental Modelling: A Practical Introduction using Excel
J. Hardisty, D. M. Taylor & S. E. Metcalfe
Chichester, Wiley, 1993, 204 pp., £14.95
Keeping Pace with Science and Engineering: Case Studies in Environmental Regulation
Washington DC, US National Academy of Engineering, 1993
World Without End: Economics, Environment and Sustainable Development
D. W. Pearce & J. J. Warford
Oxford University Press, New York, 1993, 440 pp., £35.95 相似文献
13.
14.
15.
16.
17.
18.
19.
20.