  We perform a glueball-relevant study on isoscalars based on anisotropic
$N_f=2$ lattice QCD gauge configurations. In the scalar channel, we identify
the ground state obtained through gluonic operators to be a single-particle
state through its dispersion relation. When $q\bar{q}$ operator is included, we
find the mass of this state does not change, and the $q\bar{q}$ operator
couples very weakly to this state. So this state is most likely a glueball
state. For pseudoscalars, along with the exiting lattice results, our study
implies that both the conventional $q\bar{q}$ state $\eta_2$ (or $\eta'$ in
flavor $SU(3)$) and a heavier glueball-like state with a mass of roughly 2.6
GeV exist in the spectrum of lattice QCD with dynamical quarks.
