全文获取类型
收费全文 | 283篇 |
免费 | 9篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 8篇 |
废物处理 | 9篇 |
环保管理 | 48篇 |
综合类 | 65篇 |
基础理论 | 55篇 |
环境理论 | 1篇 |
污染及防治 | 81篇 |
评价与监测 | 10篇 |
社会与环境 | 13篇 |
灾害及防治 | 4篇 |
出版年
2023年 | 4篇 |
2022年 | 3篇 |
2021年 | 6篇 |
2020年 | 5篇 |
2019年 | 7篇 |
2018年 | 3篇 |
2017年 | 6篇 |
2016年 | 11篇 |
2015年 | 10篇 |
2014年 | 9篇 |
2013年 | 25篇 |
2012年 | 12篇 |
2011年 | 27篇 |
2010年 | 22篇 |
2009年 | 12篇 |
2008年 | 19篇 |
2007年 | 12篇 |
2006年 | 8篇 |
2005年 | 5篇 |
2004年 | 11篇 |
2003年 | 8篇 |
2002年 | 6篇 |
2001年 | 5篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 6篇 |
1991年 | 1篇 |
1990年 | 5篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1973年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1964年 | 1篇 |
1963年 | 1篇 |
1957年 | 1篇 |
1928年 | 1篇 |
排序方式: 共有294条查询结果,搜索用时 8 毫秒
111.
112.
Understanding resource-based communities (RBCs) as potential casualties of Canada's economic proclivity towards resource extraction projects may help us to generate political support for these communities at both local and national scales. The media has a critical role to play in promoting the development of this type of political discourse. This study examines how traditional print media coverage affects Canadians' perceptions of the Athabasca oil sands. A quantitative media analysis examines scope and thematic content of articles appearing in major Canadian newspapers between 2003 and 2013. We find that most coverage concerning the Athabasca oil sands over this period appears predominantly in western Canadian newspapers, with coverage primarily focusing on specific events. We argue that this geographic disparity in coverage does not provide Canadians with the adequate coverage necessary to develop an informed opinion on what the implications of ongoing oil sands development are at both a local and a national scale. 相似文献
113.
Gas-phase photolytic production of hydroxyl radicals in an ultraviolet purifier for air and surfaces
David R. Crosley Melanie Doyle-Eisele Jacob D. McDonald 《Journal of the Air & Waste Management Association (1995)》2017,67(2):231-240
We have measured the concentration of hydroxyl radicals (OH) produced in the gas phase by a commercially available purifier for air and surfaces, using the time rate of decay of n-heptane added to an environmental chamber. The hydroxyl generator, an Odorox® BOSS? model, produces the OH through 185-nm photolysis of ambient water vapor. The steady-state concentration of OH produced in the 120 m3 chamber is, with 2σ error bars, (3.25 ± 0.80) × 106 cm?3. The properties of the hydroxyl generator, in particular the output of the ultraviolet lamps and the air throughput, together with an estimation of the water concentration, were used to predict the amount of OH produced by the device, with no fitted parameters. To relate this calculation to a steady-state concentration, we must estimate the OH loss rate within the chamber owing to reaction with the n-heptane and the 7 ppb of background hydrocarbons that are present. The result is a predicted steady-state concentration in excellent agreement with the measured value. This shows we understand well the processes occurring in the gas phase during operation of this hydroxyl radical purifier.Implications: Hydroxyl radical air purifiers are used for cleaning both gaseous contaminants, such as volatile organic compounds (VOCs) or hazardous gases, and biological pathogens, both airborne and on surfaces. This is the first chemical kinetic study of such a purifier that creates gas-phase OH by ultraviolet light photolysis of H2O. It shows that the amount of hydroxyls produced agrees well with nonparameterized calculations using the purifier lamp output and device airflow. These results can be used for designing appropriate remediation strategies. 相似文献
114.
Costs and consequences of variation in the size of ruff leks 总被引:2,自引:0,他引:2
Jacob Höglund Robert Montgomerie Fredrik Widemo 《Behavioral ecology and sociobiology》1993,32(1):31-39
Summary We studied 13 ruff leks in a small region on the island of Gotland (Sweden) to investigate the effect of lek size on the costs and benefits of lekking for individual males. Male ruffs occur in two behaviourally and morphologically distinct forms, independents (residents plus marginals) and satellites, whose costs and benefits we have assessed separately. These ruff leks had from 1–10 resident (territory-holding) males and were visited daily by satellites, marginals and females from 5–25 May, when most copulations occurred. We used the average number of independent males, counted during censuses taken every 5 min during 2-h observation periods at each lek, as an index of mean lek size. Per independent male, the numbers of both satellites and females increased significantly with mean lek size. Female arrival rate and attendance (total female-minutes) also increased significantly with mean lek size as did the average per capita rate of mating success for resident males (that of satellites was not quite significant). Thus, the dispersion of both of these male categories did not appear to fit an ideal free distribution with respect to mating success. In addition, the number of independent-independent fights per independent and the rate of satellite-resident dyad formation per resident increased significantly with mean lek size. These results suggest that ruffs on larger leks enjoy higher mating success than those on smaller leks but also that costs increase with lek size. We suggest that independent males distribute themselves so as to maximize their own net benefits and that this factor can account for both the occurrence of ruff leks and the variation in their size.
Correspondence to: J. Höglund 相似文献
115.
116.
117.
118.
119.
120.