  Let (X,0) be a germ of complex analytic normal variety, non-singular outside
0. An essential divisor over (X,0) is a divisorial valuation of the field of
meromorphic functions on (X,0), whose center on any resolution of the germ is
an irreducible component of the exceptional locus. The Nash map associates to
each irreducible component of the space of arcs through 0 on X the unique
essential divisor intersected by the strict transform of the generic arc in the
component. Nash proved its injectivity and asked if it was bijective. We prove
that this is the case if there exists a divisorial resolution \pi of (X,0) such
that its reduced exceptional divisor carries sufficiently many \pi-ample
divisors (in a sense we define). Then we apply this criterion to construct an
infinite number of families of 3-dimensional examples, which are not
analytically isomorphic to germs of toric 3-folds (the only class of normal
3-fold germs with bijective Nash map known before).
