Perhaps you should try some spelling variations:
mohan rai » mohana rao, milan rai, mohan r
r mohan » _ mohan
m cohen » _ cohen, b cohen, p cohen
j cohen » _ cohen
raja r » raja _, raja j, raja m

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: (( raja r mohan rai ) OR ( raja ((m cohen) OR (j cohen)) roy )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( raja r mohan rai ) or ( raja ((m cohen) OR (j cohen)) roy ))".
• Adding a wildcard symbol may retrieve word variants: (( raja r mohan rai ) or ( raja ((m cohen) OR (j cohen)) roy ))*.