  We are concerned with global steady subsonic flows through general infinitely
long nozzles for the full Euler equations. The problem is formulated as a
boundary value problem in the unbounded domain for a nonlinear elliptic
equation of second order in terms of the stream function. It is established
that, when the oscillation of the entropy and Bernoulli functions at the
upstream is sufficiently small in $C^{1,1}$ and the mass flux is in a suitable
regime, there exists a unique global subsonic solution in a suitable class of
general nozzles. The assumptions are required to prevent from the occurrence of
supersonic bubbles inside the nozzles. The asymptotic behavior of subsonic
flows at the downstream and upstream, as well as the critical mass flux, have
been clarified.
