  Let $k$ be a finite field, a $p$-adic field or a number field. Let $K$ be a
finite extension of the Laurent series field in $m$ variables
$k((x_1,...,x_m))$ or, more generally, a finite extension of the field of
rational functions $k((x_1,...,x_m))(y_1,...,y_n)$. When $r$ is an integer, we
consider the Galois module $\mathbb{Q}/\mathbb{Z}(r)$ over $K$ and we prove
several vanishing theorems for its cohomology. In the particular case when $K$
is a finite extension of the Laurent series field in two variables
$k((x_1,x_2))$, we also prove exact sequences that play the role of the
Brauer-Hasse-Noether exact sequence for the field $K$ and that involve some of
the cohomology groups of $\mathbb{Q}/\mathbb{Z}(r)$ which do not vanish.
