Let $p$ and $q$ be locally H\"{o}lder functions in $\RR^N$, $p>0$ and $q\geq
0$. We study the Emden-Fowler equation $-\Delta u+ q(x)|\nabla
u|^a=p(x)u^{-\gamma}$ in $\RR^N$, where $a$ and $\gamma$ are positive numbers.
Our main result establishes that the above equation has a unique positive
solutions decaying to zero at infinity. Our proof is elementary and it combines
the maximum principle for elliptic equations with a theorem of Crandall,
Rabinowitz and Tartar.