Secondary in abundance are aromatic sester and sesquiterpenoid hydrocarbons,but aromatic diterpenoids, most of the regular PAH are found at trace levels only.

但芳香二萜类，大多数常规多环芳烃仅以微量形式存在。

Abstract A method is suggested to determine the absolute configuration of ent kaurene diterpenoids by analysing the circular dichroism spectral data of 13 hydroxy ent kaurenoids.

摘要通过系列13羟基对映贝壳杉烯二萜的园二色散光谱的数据分析，提出一种确定对映贝壳杉烯二萜绝对构型的方法。