Observe Germany is leading European research centre (7)
I believe the answer is:
discern
'observe' is the definition.
(thesaurus)
'germany is leading european research centre' is the wordplay.
'germany' becomes 'd' (vehicle registration code for Deutschland).
'leading' means one lot of letters go next to another.
'european research centre' becomes 'CERN' (scientific research centre CERN).
'd'+'is'+'cern'='DISCERN'
(Other definitions for discern that I've seen before include "Pick out" , "Notice" , "Recognise, find out" , "Espy" , "Perceive - distinguish" .)