全文获取类型
收费全文 | 859篇 |
免费 | 3篇 |
国内免费 | 3篇 |
专业分类
安全科学 | 16篇 |
废物处理 | 16篇 |
环保管理 | 133篇 |
综合类 | 272篇 |
基础理论 | 149篇 |
污染及防治 | 200篇 |
评价与监测 | 47篇 |
社会与环境 | 25篇 |
灾害及防治 | 7篇 |
出版年
2020年 | 7篇 |
2018年 | 16篇 |
2017年 | 10篇 |
2016年 | 16篇 |
2015年 | 13篇 |
2014年 | 20篇 |
2013年 | 68篇 |
2012年 | 23篇 |
2011年 | 31篇 |
2010年 | 23篇 |
2009年 | 22篇 |
2008年 | 33篇 |
2007年 | 35篇 |
2006年 | 19篇 |
2005年 | 21篇 |
2004年 | 35篇 |
2003年 | 19篇 |
2002年 | 24篇 |
2001年 | 12篇 |
2000年 | 13篇 |
1999年 | 18篇 |
1998年 | 8篇 |
1997年 | 12篇 |
1996年 | 17篇 |
1995年 | 12篇 |
1994年 | 25篇 |
1993年 | 7篇 |
1991年 | 7篇 |
1990年 | 8篇 |
1988年 | 6篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1980年 | 9篇 |
1979年 | 7篇 |
1978年 | 7篇 |
1977年 | 7篇 |
1968年 | 7篇 |
1965年 | 6篇 |
1964年 | 9篇 |
1963年 | 6篇 |
1962年 | 6篇 |
1961年 | 6篇 |
1960年 | 8篇 |
1959年 | 11篇 |
1957年 | 7篇 |
1956年 | 11篇 |
1954年 | 9篇 |
1939年 | 6篇 |
1924年 | 6篇 |
排序方式: 共有865条查询结果,搜索用时 562 毫秒
501.
Sanchez-Azofeifa G. Arturo Skole David L. Chomentowski Walter 《Mitigation and Adaptation Strategies for Global Change》1997,2(2-3):177-189
One of the concerns regarding transformation of land cover in tropical areas has been the large degree of uncertainty associated with both rates of deforestation over time and total deforestation. Special monitoring mechanisms must be taken into consideration if a program toward deforestation control is going to be implemented at the national or regional scale. The premise of this paper is that any attempt to quantify tropical deforestation and deforestation rates—at regional level, by randomly selecting sites within a population of satellite scenes—would require an overwhelming number of samples. This paper suggests a methodological approach for sampling remote sensing databases to be used as part of land use/cover change or joint implementation projects. This paper uses the concept of stratification and persistence as main tools. 相似文献
502.
503.
504.
505.
506.
Gabriela Rosiles-González Gerardo Ávila-Torres Oscar A. Moreno-Valenzuela Gilberto Acosta-González Rosa María Leal-Bautista Cinthya D. Grimaldo-Hernández Judith K. Brown Cristóbal Chaidez-Quiroz Walter Q. Betancourt Charles P. Gerba Cecilia Hernández-Zepeda 《Food and environmental virology》2017,9(4):487-497
The Yucatan Peninsula of Mexico hosts a karst aquifer system that is the only source of freshwater for the area; however, it is vulnerable to human-mediated contamination. Pepper mild mottle virus (PMMoV) is one of the most abundant RNA viruses associated with human feces, making it a viable indicator for tracking fecal pollution in aquatic environments, including groundwater. In this study, groundwater samples collected from a karst aquifer from fresh and brackish water locations were analyzed for fecal indicator bacteria, somatic and male F+ specific coliphages, and PMMoV during the rainy and dry seasons. Total coliform bacteria were detected at all sites, whereas Escherichia coli were found at relatively low levels <40 MPN/100 ml. The highest average concentrations of somatic and male F+ specific coliphages were 920 and 330 plaque forming units per 100 ml, respectively, detected in freshwater during the rainy season. PMMoV RNA was detected in 85% of the samples with gene sequences sharing 99–100% of nucleotide identity with PMMoV sequences available in GenBank. Quantification of PMMoV genome copies (GC) by quantitative real-time PCR indicated concentrations ranging from 1.7 × 101 to 1.0 × 104 GC/L, with the highest number of GC detected during the rainy season. No significant correlation was observed between PMMoV occurrence by season or water type (p > 0.05). Physicochemical and indicator bacteria were not correlated with PMMoV concentrations. The abundance and prevalence of PMMoV in the karst aquifer may reflect its environmental persistence and its potential as a fecal indicator in this karst aquifer system. 相似文献
507.
508.
Diane Van Opstal Geerke M. Eggenhuizen Marieke Joosten Karin Diderich Lutgarde Govaerts Robert-Jan Galjaard Attie Go Maarten Knapen Marjan Boter Wai Y. Cheung Nicole van Koetsveld Stefanie van Veen Walter G. de Valk Fernanda Jehee Femke de Vries Iris Hollink Lies Hoefsloot Malgorzata Srebniak 《黑龙江环境通报》2020,40(10):1338-1342
509.
510.