The investigation of nonlinear oscillation is very important for the nonlinear science. Many methods have been advanced to study weakly nonlinear system, including multiple scale method, KBM method, averaging method, and so on.

• 非线性振动理论是非线性科学的一个重要研究内容，对于弱非线性常微分方程控制的动力系统已经有了许多求近似解的方法，如多尺度法、KBM法、平均法等等。