- 基本原理 jīběnyuánlǐ fundamental principlefundamental principle; the basic doctrine or law that forms the foundation of a system
- 不相容原理 bùxiāngróngyuánlǐ exclusion principle(Pauli) exclusion principle (physics)
- 不确定性原理 bùquèdìngxìngyuánlǐ uncertainty principleHeisenberg's uncertainty principle (1927)
- 变分原理 biànfēnyuánlǐ variational principlevariational principle (physics)
