Perhaps you should try some spelling variations:
retrieval conference » retrieval inference, retrieval preference, pretrial conferences
retrieval references » removal references, general references, retrieval services
retinal conference » regional conference, regional conferences, national conference
elgar retinal » tear retinal, ar retinal

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: (( elgar retinal conference ) OR ( delay ((retrieval conference) OR (retrieval references)) )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( elgar retinal conference ) or ( delay ((retrieval conference) OR (retrieval references)) ))".
• Adding a wildcard symbol may retrieve word variants: (( elgar retinal conference ) or ( delay ((retrieval conference) OR (retrieval references)) ))*.