  We introduce the Callan-Symanzik method in the description of anisotropic as
well as isotropic Lifshitz critical behaviors. Renormalized perturbation
theories are defined by normalization conditions with nonvanishing masses and
at zero external momenta. The orthogonal approximation is employed to obtain
the critical indices $\eta_{L2}$, $\nu_{L2}$, $\eta_{L4}$ and $\nu_{L4}$
diagramatically at least up to two-loop order in the anisotropic criticalities.
This approximation is also utilized to compute the exponents $\eta_{L4}$ and
$\nu_{L4}$ in the isotropic case. Furthermore, we compute those exponents
exactly for the isotropic behaviors at the same loop order. The results
obtained for all exponents are in perfect agreement with those previously
derived in the massless theories renormalized at nonzero external momenta.
