  We consider the problem of sliding motion of a charge-density-wave subject to
static disorder within an elastic medium model. Starting with a
field-theoretical formulation, which allows exact disorder averaging, we
propose a self-consistent approximation scheme to obtain results beyond the
standard large-velocity expansion. Explicit calculations are carried out in
three spatial dimensions. For the conductivity, we find a strong-coupling
regime at electrical fields just above the pinning threshold. Phase and
velocity correlation functions scale differently from the high-field regime,
and static phase correlations converge to the pinned-phase behaviour. The
sliding charge-density-wave is accompanied by narrow-band noise.
