Perhaps you should try some spelling variations:
biologe » biologie, biology, biologia
biologen » biologien, biologyn, biologian, biology, biologie
biologic » biologie, biological, biology
biologian » biologia, biologin, biologiae

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: ((biologe OR biologic) OR (biologen OR biologian)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((biologe or biologic) or (biologen OR biologian))".
• Adding a wildcard symbol may retrieve word variants: ((biologe or biologic) or (biologen OR biologian))*.