Perhaps you should try some spelling variations:
transfer operations » transfer operators, transport operations, transit operations
transfer axiom » transfer from, transfer asia
head transfer » heat transfer, heart transfer, load transfer
luis rdf » luis f, luis de
rdf head » red head
a der » _ der, 2 der, 1 der
3 der » _ der, 2 der

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: (( luis ((a der) OR (3 der)) transfer axiom martin ) OR ( luis rdf head transfer operations _ ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( luis ((a der) OR (3 der)) transfer axiom martin ) or ( luis rdf head transfer operations _ ))~".
• Adding a wildcard symbol may retrieve word variants: (( luis ((a der) OR (3 der)) transfer axiom martin ) or ( luis rdf head transfer operations _ ))*.