  In this work we incorporate, in a unified way, two anomalous behaviors, the
power law and stretched exponential ones, by considering the radial dependence
of the $N$-dimensional nonlinear diffusion equation $\partial\rho
/\partial{t}={\bf \nabla} \cdot (K{\bf \nabla} \rho^{\nu})-{\bf
\nabla}\cdot(\mu{\bf F} \rho)-\alpha \rho ,$ where $K=D r^{-\theta}$, $\nu$,
$\theta$, $\mu$ and $D$ are real parameters and $\alpha$ is a time-dependent
source. This equation unifies the O'Shaugnessy-Procaccia anomalous diffusion
equation on fractals ($\nu =1$) and the spherical anomalous diffusion for
porous media ($\theta=0$). An exact spherical symmetric solution of this
nonlinear Fokker-Planck equation is obtained, leading to a large class of
anomalous behaviors. Stationary solutions for this Fokker-Planck-like equation
are also discussed by introducing an effective potential.
