Five-dimensional space-time string cosmological models generated by a cloud of strings with particles attached to them are studied in the Brans-Dicke theory.We obtain two types of interesting models by taking up the cases of geometric strings (or Nambu strings) and p-strings (Takabayasi strings),and study their different physical and dynamical properties.The roles of the scalar field in getting different phases,such as the inflationary phase and the string-dominated phase,are discussed.An interesting feature obtained here is that in one of the models there is a "bounce" at a particular instant of its evolution.