The molecular flow, or effusion limit, of transport through a capillary is extended to include the regime where the effects of intermolecular scattering become important. This is accomplished through a generalization of the Clausing equation, which gives a fundamental kinetic theory description of molecular flow. The generalized integral equation obtained is solved numerically to obtain both throughput and angular distribution properties of the gas flow. The results show good agreement with experimental curves which clearly demonstrate the effects of intermolecular scattering.