1. 信条;主义;学说;（尤指）宗教教义
    A doctrine is a set of principles or beliefs, especially religious ones.

    e.g. ...the doctrine of reincarnation.
           轮回转世说
    e.g. I disagree with the doctrine that the writer's life and intention have no bearing on his texts.
           我不同意作者的生活和意图与他的文本没有联系的学说。

2. (尤指政府外交政策的)正式声明
    A doctrine is a statement of official government policy, especially foreign policy.

    e.g. Following World War II, the first U.S. commitment to Europe came in the form of the 1947 Truman Doctrine.
           二战后，美国对欧洲作出的第一个承诺便是在 1947 年提出杜鲁门主义。