全文获取类型
收费全文 | 767篇 |
免费 | 10篇 |
国内免费 | 4篇 |
专业分类
安全科学 | 59篇 |
废物处理 | 42篇 |
环保管理 | 138篇 |
综合类 | 68篇 |
基础理论 | 230篇 |
环境理论 | 1篇 |
污染及防治 | 155篇 |
评价与监测 | 61篇 |
社会与环境 | 23篇 |
灾害及防治 | 4篇 |
出版年
2023年 | 4篇 |
2022年 | 7篇 |
2019年 | 5篇 |
2018年 | 8篇 |
2017年 | 9篇 |
2016年 | 17篇 |
2015年 | 13篇 |
2014年 | 19篇 |
2013年 | 76篇 |
2012年 | 23篇 |
2011年 | 46篇 |
2010年 | 31篇 |
2009年 | 26篇 |
2008年 | 28篇 |
2007年 | 31篇 |
2006年 | 50篇 |
2005年 | 21篇 |
2004年 | 18篇 |
2003年 | 26篇 |
2002年 | 33篇 |
2001年 | 23篇 |
2000年 | 27篇 |
1999年 | 12篇 |
1998年 | 15篇 |
1997年 | 11篇 |
1996年 | 12篇 |
1995年 | 13篇 |
1994年 | 10篇 |
1993年 | 9篇 |
1992年 | 9篇 |
1991年 | 9篇 |
1990年 | 11篇 |
1989年 | 7篇 |
1988年 | 8篇 |
1987年 | 8篇 |
1986年 | 9篇 |
1985年 | 6篇 |
1984年 | 11篇 |
1983年 | 5篇 |
1982年 | 9篇 |
1981年 | 7篇 |
1980年 | 9篇 |
1979年 | 5篇 |
1978年 | 8篇 |
1977年 | 4篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1974年 | 5篇 |
1973年 | 5篇 |
1969年 | 3篇 |
排序方式: 共有781条查询结果,搜索用时 211 毫秒
491.
492.
493.
494.
Steven J. Dutton Daniel E. Williams Jessica K. Garcia Sverre Vedal Michael P. Hannigan 《Atmospheric environment (Oxford, England : 1994)》2009,43(12):2018-2030
Particulate matter less than 2.5 microns in diameter (PM2.5) has been shown to have a wide range of adverse health effects and consequently is regulated in accordance with the US-EPA's National Ambient Air Quality Standards. PM2.5 originates from multiple primary sources and is also formed through secondary processes in the atmosphere. It is plausible that some sources form PM2.5 that is more toxic than PM2.5 from other sources. Identifying the responsible sources could provide insight into the biological mechanisms causing the observed health effects and provide a more efficient approach to regulation. This is the goal of the Denver Aerosol Sources and Health (DASH) study, a multi-year PM2.5 source apportionment and health study.The first step in apportioning the PM2.5 to different sources is to determine the chemical make-up of the PM2.5. This paper presents the methodology used during the DASH study for organic speciation of PM2.5. Specifically, methods are covered for solvent extraction of non-polar and semi-polar organic molecular markers using gas chromatography–mass spectrometry (GC–MS). Vast reductions in detection limits were obtained through the use of a programmable temperature vaporization (PTV) inlet along with other method improvements. Results are presented for the first 1.5 years of the DASH study revealing seasonal and source-related patterns in the molecular markers and their long-term correlation structure. Preliminary analysis suggests that point sources are not a significant contributor to the organic molecular markers measured at our receptor site. Several motor vehicle emission markers help identify a gasoline/diesel split in the ambient data. Findings show both similarities and differences when compared with other cities where similar measurements and assessments have been made. 相似文献
495.
496.
497.
498.
499.
A dispersal-constrained habitat suitability model for predicting invasion of alpine vegetation 总被引:1,自引:0,他引:1
Developing tools to predict the location of new biological invasions is essential if exotic species are to be controlled before they become widespread. Currently, alpine areas in Australia are largely free of exotic plant species but face increasing pressure from invasive species due to global warming and intensified human use. To predict the potential spread of highly invasive orange hawkweed (Hieracium aurantiacum) from existing founder populations on the Bogong High Plains in southern Australia, we developed an expert-based, spatially explicit, dispersal-constrained, habitat suitability model. The model combines a habitat suitability index, developed from disturbance, site wetness, and vegetation community parameters, with a phenomenological dispersal kernel that uses wind direction and observed dispersal distances. After generating risk maps that defined the relative suitability of H. aurantiacum establishment across the study area, we intensively searched several locations to evaluate the model. The highest relative suitability for H. aurantiacum establishment was southeast from the initial infestations. Native tussock grasslands and disturbed areas had high suitability for H. aurantiacum establishment. Extensive field searches failed to detect new populations. Time-step evaluation using the location of populations known in 1998-2000, accurately assigned high relative suitability for locations where H. aurantiacum had established post-2003 (AUC [area under curve] = 0.855 +/- 0.035). This suggests our model has good predictive power and will improve the ability to detect populations and prioritize areas for ongoing monitoring. 相似文献
500.