Cetaceans reduce the number of breaths they take during rest periods.鲸类动物在休息时减少它们的呼吸次数.It is not clear whether cetaceans undergo dream sleep.鲸类动物是否经历梦睡眠还不清楚.Missing until recently were fossils clearly intermediate, or tr...
In micrographics a device for holding a frame, or frames, of microfilm.在缩微图形技术中,用于固定一帧或多帧缩微胶片的装置.In micrographics, a device that enlarges microimages for viewing.在缩微照相技术中, 放大图形以便观察的一种设备....