Perhaps you should try some spelling variations:
del literatur » model literatur, teil literatur, igel literatur
tool studies » tombol studies, dmol studies, qol studies
studies la » studies lab, studies lca, studies lia
test tool » test tools, best tool, test two

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

• Adding a wildcard symbol may retrieve word variants: test tool studies la filosofia del literatur*.