theory of equations meaning in Chinese

方程论
方程式论

In this paper , we principally expound the fundamental theory of equation of state , theoretical models on equation of state of solids , basis of approximation , and applicable semi - empirical , semi - theoretical equation of state of solids
本论文论述了物态方程的基本理论，固体物态方程建立的理论模型、近似基础，和具有实用价值的半经验、半理论的唯象固体态方程等。