全文获取类型
收费全文 | 338篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 4篇 |
废物处理 | 15篇 |
环保管理 | 36篇 |
综合类 | 55篇 |
基础理论 | 73篇 |
污染及防治 | 128篇 |
评价与监测 | 24篇 |
社会与环境 | 7篇 |
灾害及防治 | 1篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 7篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 16篇 |
2017年 | 10篇 |
2016年 | 9篇 |
2015年 | 4篇 |
2014年 | 8篇 |
2013年 | 21篇 |
2012年 | 14篇 |
2011年 | 24篇 |
2010年 | 9篇 |
2009年 | 7篇 |
2008年 | 23篇 |
2007年 | 21篇 |
2006年 | 15篇 |
2005年 | 19篇 |
2004年 | 10篇 |
2003年 | 12篇 |
2002年 | 15篇 |
2001年 | 7篇 |
2000年 | 7篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 8篇 |
1996年 | 13篇 |
1995年 | 8篇 |
1994年 | 5篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1983年 | 1篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1978年 | 2篇 |
1973年 | 1篇 |
1965年 | 1篇 |
1960年 | 3篇 |
1959年 | 2篇 |
1958年 | 2篇 |
1957年 | 1篇 |
1956年 | 1篇 |
1955年 | 2篇 |
1954年 | 1篇 |
排序方式: 共有343条查询结果,搜索用时 15 毫秒
341.
342.
In the buoyancy and turbulence-driven atmospheric circulations (BTDAC) that occur over urban areas where the approach means wind speeds are very low (less than turbulent fluctuations and typically < 3 m/sec), the surface temperatures are significantly higher than those in the external rural areas, and the atmosphere above the mixing layer is stably stratified. In this paper, the mechanisms of BTDAC formation are studied through laboratory experiments and modelling, with additional low-level inflow from external rural areas and a divergent outflow in the opposite direction in the upper part of the mixed layer. Strong turbulent plumes in the central region mix the flow between lower and higher levels up to the inversion height. There are shear-driven turbulent eddies and weaker buoyant plumes around the periphery of the urban area. As the approach flow is very weak, the recirculating streamlines within the dome restrict the ventilation, and the dispersion of pollution emitted from sources below the inversion height leading to a rise in the mean concentration. Low-level air entrained from rural areas can, however, improve ventilation and lower this concentration. This trend can also be improved if the recirculating structure of the BTDAC flow pattern over urban areas breaks down as a result of the surface temperature distribution not being symmetrical, or as the approach wind speed increases to a level comparable with the mean velocity of circulation, or (except near the equator) the urban area is large enough that the Coriolis acceleration is significant. 相似文献
343.
Efremova KO Volodin IA Volodina EV Frey R Lapshina EN Soldatova NV 《Die Naturwissenschaften》2011,98(11):919-931
In goitred gazelles (Gazella subgutturosa), sexual dimorphism of larynx size and position is reminiscent of the case in humans, suggesting shared features of vocal
ontogenesis in both species. This study investigates the ontogeny of nasal and oral calls in 23 (10 male and 13 female) individually
identified goitred gazelles from shortly after birth up to adolescence. The fundamental frequency (f0) and formants were measured
as the acoustic correlates of the developing sexual dimorphism. Settings for LPC analysis of formants were based on anatomical
dissections of 5 specimens. Along ontogenesis, compared to females, male f0 was consistently lower both in oral and nasal
calls and male formants were lower in oral calls, whereas the first two formants of nasal calls did not differ between sexes.
In goitred gazelles, significant sex differences in f0 and formants appeared as early as the second week of life, while in
humans they emerge only before puberty. This result suggests different pathways of vocal ontogenesis in the goitred gazelles
and in humans. 相似文献