Guanine A nitrogenous base found in DNA and RNA.Guanine has a pruine ring structure.

是存在于DNA与RNA中的一种含氮碱基，具有一个嘌呤环结构。

Preoxygenation replaces the primarily nitrogenous mixture of ambient air, which constitutes the patient's functional residual capacity, with oxygen.

这样可以用氧被氮占据的肺泡。

Malt extract is made by extracting the soluble products from sprouted grain,used in mycological as a source of carbohydrate and nitrogenous.

性状本品系大麦提的水溶物，用于配制真菌培养基，提供碳水化合物及氮源。