  A complete qualitative study of the dynamics of string cosmologies is
presented for the class of isotopic curvature universes. These models are of
Bianchi types I, V and IX and reduce to the general class of
Friedmann-Robertson-Walker universes in the limit of vanishing shear isotropy.
A non-trivial two-form potential and cosmological constant terms are included
in the system. In general, the two-form potential and spatial curvature terms
are only dynamically important at intermediate stages of the evolution. In many
of the models, the cosmological constant is important asymptotically and
anisotropy becomes dynamically negligible. There also exist bouncing
cosmologies.
