Beside each subject heading will be the number of corresponding entries in the database. You can choose a more specific heading if you like.
Note that if you choose a subject
heading which has children, all of the children may or may not be included
along with it. Inclusion of the children is called exploding
the term. Normally it happens by default. If you go into the tree display
then it doesn't happen by default, but you can
check on the Explode
box if desired.