全文获取类型
收费全文 | 245篇 |
免费 | 2篇 |
国内免费 | 3篇 |
专业分类
安全科学 | 22篇 |
废物处理 | 8篇 |
环保管理 | 44篇 |
综合类 | 36篇 |
基础理论 | 54篇 |
污染及防治 | 48篇 |
评价与监测 | 11篇 |
社会与环境 | 22篇 |
灾害及防治 | 5篇 |
出版年
2024年 | 1篇 |
2022年 | 5篇 |
2021年 | 10篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 6篇 |
2017年 | 14篇 |
2016年 | 16篇 |
2015年 | 14篇 |
2014年 | 5篇 |
2013年 | 11篇 |
2012年 | 12篇 |
2011年 | 16篇 |
2010年 | 13篇 |
2009年 | 11篇 |
2008年 | 8篇 |
2007年 | 18篇 |
2006年 | 7篇 |
2005年 | 8篇 |
2004年 | 9篇 |
2003年 | 4篇 |
2002年 | 8篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 4篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 6篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1976年 | 1篇 |
1964年 | 1篇 |
1959年 | 2篇 |
1951年 | 1篇 |
1950年 | 1篇 |
1948年 | 1篇 |
1946年 | 1篇 |
1940年 | 1篇 |
1936年 | 2篇 |
排序方式: 共有250条查询结果,搜索用时 46 毫秒
21.
Swetnam RD Owen Mountford J Manchester SJ Broughton RK 《Journal of environmental management》2004,71(1):79-93
This paper explores whether the introduction of an agri-environmental scheme has altered the course of long-term trends in plant species abundance in the Somerset Levels and Moors Environmentally Sensitive Area (ESA), UK. A semi-quantitative approach has been taken which integrates disparate but important historical datasets relating to flora and land management with more contemporary digital information. Species datasets from four time periods throughout the 20th century have been collated within a Geographic Information System and analysed with respect to ancillary data relating to elevation, under-drainage and ESA designation. Qualitative reconstruction of the historical ecology of this internationally important area of lowland wet grassland showed that a steady decline in abundance and extent of key components of the flora had already started by 1900. Analysis of historical under-drainage records dating from 1940s to 1980s showed a clear link between the length of time an area had been under-drained and the subsequent diversity of flora recorded in later surveys. In addition, the relative persistence of the rarer components of the wetland flora between surveys in 1980 and 1997 was related to the spatial pattern of under-drainage on the site since 1940. When overall species diversity was compared before and after ESA designation (1980-1997) there was some evidence of an increase in the number of species present and their spatial extent. The historical dataset provided useful contextual information with respect to species trends and allowed the interpretation of contemporary datasets to be placed within a longer timeframe. This pilot study using 18 species gives some evidence that long-established trends in species decline in the Somerset Levels and Moors ESA are starting to be reversed. 相似文献
22.
Haug R 《Disasters》2002,26(1):70-84
The Hawaweer, a nomadic, pastoralist group in northern Sudan, were seriously affected by the drought in the Sahel during the mid-1980s. Their experience illustrates the connection between internally displaced people, normal mobility, forced migration, dilemmas and opportunities of return and how new livelihoods can be successfully constructed based on traditional rights, strong local institutions and external resources. Some displaced Hawaweer got the chance to return to their homeland as new livelihood opportunities were established; others did not get this opportunity nor would they have returned if they had been given the chance. In both situations, the processes of displacement and return had an impact on the sense of belonging and identity. 相似文献
23.
24.
Karen L. Stals Matthew Wakeling Júlia Baptista Richard Caswell Andrew Parrish Julia Rankin Carolyn Tysoe Garan Jones Adam C. Gunning Hana Lango Allen Lisa Bradley Angela F. Brady Helena Carley Jenny Carmichael Bruce Castle Deirdre Cilliers Helen Cox Charu Deshpande Abhijit Dixit Jacqueline Eason Frances Elmslie Andrew E. Fry Alan Fryer Muriel Holder Tessa Homfray Emma Kivuva Victoria McKay Ruth Newbury-Ecob Michael Parker Ravi Savarirayan Claire Searle Nora Shannon Deborah Shears Sarah Smithson Ellen Thomas Peter D. Turnpenny Vinod Varghese Pradeep Vasudevan Emma Wakeling Emma L. Baple Sian Ellard 《黑龙江环境通报》2018,38(1):33-43
针对传统教与学算法在解决复杂多峰函数优化问题时,具有局部最优且搜索开发能力较差的缺点,提出了一种改进的多学习教与学优化算法,新算法为学员的每一维加入不同的教学因子,设计了基于学员均值比较的教师选择策略和向教师及学员学习的多学习策略。基于多个单峰和多峰函数的仿真结果表明,新算法跟传统的、改进的教与学算法相比,在稳定性、寻优精度和收敛速度方面更具优势。 相似文献
25.
26.
27.
Ruth F. Weiner Daniel A. Jaffe 《Journal of the Air & Waste Management Association (1995)》2013,63(8):797-801
An analysis was made of 49 applications for PSD permits in EPA Region X. Factors studied included the time needed to secure a permit, the regulation which determined the permit (BACT, NSPS, the PSD increment state regulation) and differences in suggested control techniques between EPA and the applicant. These factors were correlated with the category of industry applying for the permit and potential, reduction in air contamination. 相似文献
28.
In the present study the water movement in a bottom ash landfill from a municipal solid waste incinerator (MSWI) was investigated. The pore regime of such landfills consists of macropores (with diameter > 50 microm), which make up about two-thirds of the total porosity and micropores. The program MACRO, which describes flow through porous media and takes both macro- and micropore flows into account, was applied. The model was calibrated with a time series from the landfill Riet, near Winterthur in Switzerland. In the present study the model was recalibrated at a time series for 1 year. With this scenario the influence of an expected reduction or increase of the porosity on leachate behaviour of such landfills over a long time (> 100 years) was studied ('long-term behaviour'). It has been shown that reliable information about water percolation can only be provided by obtaining more information about the hydraulic structure of such landfills. In particular, the number of macropores and the porosity exert great influence on the water movement. 相似文献
29.
This is the third update of research on graduated driver licensing (GDL) and related teenage driver issues. It briefly summarizes research published since or not included in the 2005 update (Hedlund, J., & Compton, R. (2005). Graduated driver licensing research in 2004 and 2005. Journal of Safety Research, 36(2), 109-119.), describes research in progress of which the authors are aware, and announces plans for a symposium on teenage driving and GDL to be held in February 2007. 相似文献
30.
在关于改善环境的科学与政策讨论中,最经常提到的话题之一就是如何使小型和中等规模的企业参与进来. 相似文献