Perhaps you should try some spelling variations:
life literature » polite literature, prose literature
tests safety » test safety, guests safety, stents safety
e literature » e literatur, prose literature, norse literature
studien lap » studien a, studien am, studien das
studien la » studien a, studien l, studien das

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tests safety ((studien la) OR (studien lap)) filosofia ((e literature) OR (life literature)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tests safety ((studien la) or (studien lap)) filosofia ((e literature) OR (life literature))".
• Adding a wildcard symbol may retrieve word variants: tests safety ((studien la) or (studien lap)) filosofia ((e literature) OR (life literature))*.