while (<DATA>) {
    print if /CR/ .. /NR/;
}
__DATA__
foo bar
foo
CR *FDA, 1997, GUID IND EXT REL OR
   BADAWY SIF, 1996, INT J PHARM, V128, P45
  (more lines w. similar formatting)
NR 42
more text
CR yada yada
yada yada yada
NR 17
rubbish