  The problem of steady-state accretion to nonrotating black holes is examined.
Advection is included and generalized formulas for the radiation pressure in
both the optically thick and thin cases are used. Special attention is devoted
to models with a high accretion rate. Global solutions for accretion disks are
studied which describe a continuous transition between an optically thick outer
region and an optically thin inner region. It is shown that there is a maximum
disk temperature for the model with a viscosity parameter {\alpha} = 0.5. For
the model with {\alpha} = 0.1, no optically thin regions are found to exist for
any accretion rate.
