As explained on the second page of the BIBTeX manual the new command \nocite{*} allows, since version 0.99b, to
include in the reference list every entry in the database files, without having to explicitly \cite or \nocite each entry. Giving this command, in essence, \nocites all the enties in the database, in database order, at the very spot in your document where you give the command.
This is useful since BIBTeX, by default, do not consider uncited entries of the database. This behaviour can look strange but is the right way to proceed: if you don't cite anything, it means that you haven't used any information from the entries in the database in your document! So the best way to proceed is to find a place to cite every entry.
\citecommands in your document. – Martin Scharrer♦ May 12 '11 at 10:24\nocite{*}before the bibliography command – Herbert May 12 '11 at 10:31\nocite{*}command before\printbibliography– Spike May 12 '11 at 10:34