Derived decompositions of abelian categories are introduced in internal terms of
abelian subcategories. They are used to construct semiorthogonal decompositions
(or in other terminology, Bousfield localizations, or hereditary torsion pairs) in
derived categories of abelian categories. A sufficient condition is given for
abelian categories to have derived decompositions. This is necessary if abelian
categories have enough projectives and injectives. Applications are given to
homological ring epimorphisms, localizing subcategories, nonsingular rings and
commutative noetherian rings. Moreover, a derived stratification of module
categories over commutative noetherian rings of Krull dimension at most
is
presented.