全文获取类型
收费全文 | 356篇 |
免费 | 27篇 |
出版年
2023年 | 4篇 |
2022年 | 5篇 |
2021年 | 12篇 |
2020年 | 3篇 |
2019年 | 6篇 |
2018年 | 5篇 |
2017年 | 1篇 |
2016年 | 14篇 |
2015年 | 20篇 |
2014年 | 18篇 |
2013年 | 23篇 |
2012年 | 32篇 |
2011年 | 21篇 |
2010年 | 11篇 |
2009年 | 12篇 |
2008年 | 22篇 |
2007年 | 23篇 |
2006年 | 28篇 |
2005年 | 18篇 |
2004年 | 11篇 |
2003年 | 16篇 |
2002年 | 11篇 |
2001年 | 3篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有383条查询结果,搜索用时 234 毫秒
381.
Observational studies describe rough-toothed dolphins (Steno bredanensis) actively foraging during the day on epipelagic species. Using data from depth-transmitting satellite tags deployed on nine individuals off Kauaʻi, we investigated diving behavior and the effects of lunar phase and solar light levels on vertical movements. Overall, tagged rough-toothed dolphins primarily used near-surface waters, spending between 83.6% and 93.7% of their time in the top 30 m of the water column. When diving, grand mean, median, and maximum dive depths were 76.9 m, 67.5 m, and 399.5 m, although individuals were in water with depths from approximately 700–1,450 m. Dive rates varied by time of day, being lowest during the day and at dawn and highest at dusk and night. Dives were deepest (M = 133.7 m, SD = 52.6 m, median = 106.5 m) and longest (M = 4.0 min, SD = 0.4 min, median = 4.0 min) at dusk, suggesting dolphins were taking advantage of prey rising to the surface in response to reduced light levels. Lunar phase indirectly affected diving, with deeper and longer dives occurring with increasing illumination. The variations in dive behavior across solar and lunar cycles indicate diving patterns shift based on the distribution of prey. 相似文献
382.
383.
Jacquelyn A. Kallunki 《Brittonia》1998,50(1):59-62
Andreadoxa flava is distinguished from all other genera of the neotropical subtribe Cuspariinae by the combination of a cupular calyx, yellow,
free petals narrowed at base, two glandular-punctate anthers joined by their based appendages, five apically subglobose and
glandular staminodes, a smooth papery testa, and conduplicate, plicate cotyledons. It is one of 10 monospecific genera of
the subtribe and one of 17 species of this subtribe endemic to the coastal forests of Bahia. 相似文献