  For weak dispersion and weak dissipation cases, the (1+1)-dimensional
KdV-Burgers equation is investigated in terms of approximate symmetry reduction
approach. The formal coherence of similarity reduction solutions and similarity
reduction equations of different orders enables series reduction solutions. For
weak dissipation case, zero-order similarity solutions satisfy the Painlev\'e
II, Painlev\'e I and Jacobi elliptic function equations. For weak dispersion
case, zero-order similarity solutions are in the form of Kummer, Airy and
hyperbolic tangent functions. Higher order similarity solutions can be obtained
by solving linear ordinary differential equations.
