全文获取类型
收费全文 | 338篇 |
免费 | 5篇 |
专业分类
安全科学 | 7篇 |
废物处理 | 1篇 |
环保管理 | 17篇 |
综合类 | 239篇 |
基础理论 | 49篇 |
污染及防治 | 23篇 |
评价与监测 | 3篇 |
社会与环境 | 4篇 |
出版年
2018年 | 4篇 |
2015年 | 5篇 |
2014年 | 4篇 |
2013年 | 15篇 |
2011年 | 5篇 |
2010年 | 4篇 |
2009年 | 4篇 |
2008年 | 7篇 |
2007年 | 8篇 |
2006年 | 5篇 |
2005年 | 7篇 |
2003年 | 9篇 |
2002年 | 4篇 |
2000年 | 3篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1986年 | 6篇 |
1985年 | 3篇 |
1963年 | 6篇 |
1961年 | 5篇 |
1960年 | 4篇 |
1959年 | 3篇 |
1958年 | 7篇 |
1957年 | 8篇 |
1956年 | 8篇 |
1955年 | 7篇 |
1954年 | 8篇 |
1948年 | 3篇 |
1946年 | 3篇 |
1943年 | 6篇 |
1942年 | 3篇 |
1940年 | 8篇 |
1939年 | 10篇 |
1937年 | 3篇 |
1936年 | 4篇 |
1935年 | 3篇 |
1934年 | 4篇 |
1933年 | 5篇 |
1931年 | 11篇 |
1930年 | 9篇 |
1927年 | 3篇 |
1925年 | 6篇 |
1924年 | 3篇 |
1923年 | 8篇 |
1922年 | 3篇 |
1921年 | 8篇 |
1920年 | 5篇 |
1914年 | 3篇 |
排序方式: 共有343条查询结果,搜索用时 0 毫秒
341.
Torpor and basking in a small arid zone marsupial 总被引:3,自引:3,他引:0
The high energetic cost associated with endothermic rewarming from torpor is widely seen as a major disadvantage of torpor.
We tested the hypothesis that small arid zone marsupials, which have limited access to energy in the form of food but ample
access to solar radiation, employ basking to facilitate arousal from torpor and reduce the costs of rewarming. We investigated
torpor patterns and basking behaviour in free-ranging fat-tailed dunnarts Sminthopsis crassicaudata (10 g) in autumn and winter using small, internal temperature-sensitive transmitters. Torpid animals emerged from their resting
sites in cracking soil at ∼1000 h with body temperatures as low as 14.6°C and positioned themselves in the sun throughout
the rewarming process. On average, torpor duration in autumn was shorter, and basking was less pronounced in autumn than in
winter. These are the first observations of basking during rewarming in S. crassicaudata and only the second direct evidence of basking in a torpid mammal for the reduction of energetic costs during arousal from
torpor and normothermia. Our findings suggest that although overlooked in the past, basking may be widely distributed amongst
heterothermic mammals. Therefore, the energetic benefits from torpor use in wild animals may currently be underestimated. 相似文献
342.
Yearlong hibernation in a marsupial mammal 总被引:4,自引:3,他引:1
Geiser F 《Die Naturwissenschaften》2007,94(11):941-944
Many mammals hibernate each year for about 6 months in autumn and winter and reproduce during spring and summer when they
are generally not in torpor. I tested the hypothesis that the marsupial pygmy-possum (Cercartetus nanus), an opportunistic nonseasonal hibernator with a capacity for substantial fattening, would continue to hibernate well beyond
winter. I also quantified how long they were able to hibernate without access to food before their body fat stores were depleted.
Pygmy-possums exhibited a prolonged hibernation season lasting on average for 310 days. The longest hibernation season in
one individual lasted for 367 days. For much of this time, despite periodic arousals after torpor bouts of ∼12.5 days, energy
expenditure was reduced to only ∼2.5% of that predicted for active individuals. These observations represent the first report
on body-fat-fuelled hibernation of up to an entire year and provide new evidence that prolonged hibernation is not restricted
to placental mammals living in the cold. 相似文献
343.
Wind has previously been shown to influence the location and orientation of spider web sites and also the geometry and material
composition of constructed orb webs. We now show that wind also influences components of prey-catching behaviour within the
web. A small wind tunnel was used to generate different wind speeds. Araneus diadematus ran more slowly towards entangled Drosophila melanogaster in windy conditions, which took less time to escape the web. This indicates a lower capture probability and a diminished
overall predation efficiency for spiders at higher wind speeds. We conclude that spiders’ behaviour of taking down their webs
as wind speed increases may therefore not be a response only to possible web damage. 相似文献