Defining the Jurassic-Cretaceous boundary is a controversy in stratigraphic study of the world. It has been widely accep......

以云南省曲靖地区受蠹害的云南松林为调查对象,对林内濒死树上的纵坑切梢小蠹虫和横坑切梢小蠹虫在树干的分布规律进行了研究,提出......