  We define and study Gysin morphisms on mixed motives over a perfect field.
Our construction extends the case of closed immersions, already known from
results of Voevodsky, to arbitrary projective morphisms. We prove several
classical formulas in this context, such as the projection and excess
intersection formulas, and some more original ones involving residues. Finally,
we give an application of this construction to duality and motive with compact
support.
