全文获取类型
收费全文 | 10281篇 |
免费 | 160篇 |
国内免费 | 87篇 |
专业分类
安全科学 | 399篇 |
废物处理 | 463篇 |
环保管理 | 1665篇 |
综合类 | 1350篇 |
基础理论 | 2646篇 |
环境理论 | 9篇 |
污染及防治 | 2332篇 |
评价与监测 | 704篇 |
社会与环境 | 879篇 |
灾害及防治 | 81篇 |
出版年
2023年 | 81篇 |
2022年 | 121篇 |
2021年 | 113篇 |
2020年 | 90篇 |
2019年 | 107篇 |
2018年 | 193篇 |
2017年 | 219篇 |
2016年 | 288篇 |
2015年 | 187篇 |
2014年 | 303篇 |
2013年 | 817篇 |
2012年 | 393篇 |
2011年 | 540篇 |
2010年 | 413篇 |
2009年 | 450篇 |
2008年 | 505篇 |
2007年 | 503篇 |
2006年 | 465篇 |
2005年 | 396篇 |
2004年 | 367篇 |
2003年 | 360篇 |
2002年 | 315篇 |
2001年 | 337篇 |
2000年 | 253篇 |
1999年 | 168篇 |
1998年 | 114篇 |
1997年 | 116篇 |
1996年 | 115篇 |
1995年 | 139篇 |
1994年 | 137篇 |
1993年 | 122篇 |
1992年 | 115篇 |
1991年 | 100篇 |
1990年 | 101篇 |
1989年 | 88篇 |
1988年 | 88篇 |
1987年 | 93篇 |
1986年 | 96篇 |
1985年 | 80篇 |
1984年 | 90篇 |
1983年 | 90篇 |
1982年 | 100篇 |
1981年 | 68篇 |
1980年 | 61篇 |
1979年 | 47篇 |
1978年 | 58篇 |
1977年 | 44篇 |
1976年 | 40篇 |
1974年 | 36篇 |
1972年 | 34篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
K. Bruce Jones Daniel T. Heggem Timothy G. Wade Anne C. Neale Donald W. Ebert Maliha S. Nash Megan H. Mehaffey Karl A. Hermann Anthony R. Selle Scott Augustine Iris A. Goodman Joel Pedersen David Bolgrien J. Max Viger Dean Chiang Cindy J. Lin Yehong Zhong Joan Baker Rick D. Van Remortel 《Environmental monitoring and assessment》2000,64(1):227-245
The Environmental Monitoring and Assessment Program (EMAP) is proposing an ambitious agenda to assess the status of streams and estuaries in a 12-State area of the western United States by the end of 2003. Additionally, EMAP is proposing to access landscape conditions as they relate to stream and estuary conditions across the west. The goal of this landscape project is to develop a landscape model that can be used to identify the relative risks of streams and estuaries to potential declines due to watershed-scale, landscape conditions across the west. To do so, requires an understanding of quantitative relationships between landscape composition and pattern metrics and parameters of stream and estuary conditions. This paper describes a strategic approach for evaluating the degree to which landscape composition and pattern influence stream and estuary condition, and the development and implementation of a spatially-distributed, landscape analysis approach. 相似文献
132.
Willandia A. Chaves Denis Valle Aline S. Tavares Thais Q. Morcatty David S. Wilcove 《Conservation biology》2021,35(4):1186-1197
For the first time in history, more people live in urban areas than in rural areas. This trend is likely to continue, driven largely by rural-to-urban migration. We investigated how rural-to-urban migration, urbanization, and generational change affect the consumption of wild animals. We used chelonian (tortoises and freshwater turtles), one of the most hunted taxa in the Amazon, as a model. We surveyed 1356 households and 2776 school children across 10 urban areas of the Brazilian Amazon (6 small towns, 3 large towns, and Manaus, the largest city in the Amazon Basin) with a randomized response technique and anonymous questionnaires. Urban demand for wild meat (i.e., meat from wild animals) was alarmingly high. Approximately 1.7 million turtles and tortoises were consumed in urban areas of Amazonas during 2018. Consumption rates declined as size of the urban area increased and were greater for adults than children. Furthermore, the longer rural-to-urban migrants lived in urban areas, the lower their consumption rates. These results suggest that wild meat consumption is a rural-related tradition that decreases as urbanization increases and over time after people move to urban areas. However, it is unclear whether the observed decline will be fast enough to conserve hunted species, or whether children's consumption rate will remain the same as they become adults. Thus, conservation actions in urban areas are still needed. Current conservation efforts in the Amazon do not address urban demand for wildlife and may be insufficient to ensure the survival of traded species in the face of urbanization and human population growth. Our results suggest that conservation interventions must target the urban demand for wildlife, especially by focusing on young people and recent rural to urban migrants. Article impact statement: Amazon urbanite consumption of wildlife is high but decreases with urbanization, over time for rural to urban migrants, and between generations. Impactos de la Migración del Campo a la Ciudad, la Urbanización y del Cambio Generacional sobre el Consumo de Animales Silvestres en el Amazonas 相似文献
133.
134.
135.
136.
137.
138.
David Johns 《Conservation biology》2001,15(2):543-544
139.
140.
The feasibility of adding crude glycerol from the biodiesel industry to the anaerobic digesters treating sewage sludge in wastewater treatment plants was studied in both batch and continuous experiments at 35 °C. Glycerol addition can boost biogas yields, if it does not exceed a limiting 1% (v/v) concentration in the feed. Any further increase of glycerol causes a high imbalance in the anaerobic digestion process. The reactor treating the sewage sludge produced 1106 ± 36 ml CH4/d before the addition of glycerol and 2353 ± 94 ml CH4/d after the addition of glycerol (1% v/v in the feed). The extra glycerol-COD added to the feed did not have a negative effect on reactor performance, but seemed to increase the active biomass (volatile solids) concentration in the system. Batch kinetic experiments showed that the maximum specific utilization rate (μmax) and the saturation constant (KS) of glycerol were 0.149 ± 0.015 h?1 and 0.276 ± 0.095 g/l, respectively. Comparing the estimated values with the kinetics constants for propionate reported in the literature, it can be concluded that glycerol uptake is not the rate-limiting step during the process. 相似文献