Perhaps you should try some spelling variations:
handel research » channel research, panel research, hanse research
hand research » rand research, land research, brand research
sand research » sands research, rand research, land research

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: (( online ((hand research) OR (sand research)) documents ) OR ((( online ((hand research) OR (sand research)) arguments ) OR ( online handel research study )))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( online ((hand research) OR (sand research)) documents ) or ((( online ((hand research) OR (sand research)) arguments ) or ( online handel research study ))))".
• Adding a wildcard symbol may retrieve word variants: (( online ((hand research) OR (sand research)) documents ) or ((( online ((hand research) OR (sand research)) arguments ) or ( online handel research study ))))*.