Perhaps you should try some spelling variations:
decision free » decision tree, decision trees, decision frame
event leagues » seventy leagues, seven leagues, event values
world event » world events
linz world » blind world, online world, linear world
ilec world » apec world, file world, inc world
2018 linz » 2019 linz, 2016 linz, 2018 lima
2008 ilec » 2008 isecs, 2008 ieee, 2008 iet
root » room

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: (( 2018 linz world ((robot lengthy) OR (root length)) decision free ) OR ( 2008 ilec world event leagues vision based )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( 2018 linz world ((robot lengthy) OR (root length)) decision free ) or ( 2008 ilec world event leagues vision based ))".
• Adding a wildcard symbol may retrieve word variants: (( 2018 linz world ((robot lengthy) OR (root length)) decision free ) or ( 2008 ilec world event leagues vision based ))*.