Perhaps you should try some spelling variations:
de litterature » et litterature
la litterature » a literature
de filologia » di filologia, de filosofia, e fisiologia
rat gavage » rats gavage, oral gavage
studies de » studies der, studies die, studies doe

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "rat gavage studies de filologia ((de litterature) OR (la litterature))*".