Perhaps you should try some spelling variations:
double diffusion » double diffusive, die diffusion, de diffusion
double fusion » double vision, double emulsion, double auction
double eyelid » double helix, double eged, double eye
double felix » double helix, double folio, double helixes

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: the ((((double felix) OR (double eyelid))) OR (((double fusion) OR (double diffusion)))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "the ((((double felix) or (double eyelid))) or (((double fusion) OR (double diffusion))))".
• Adding a wildcard symbol may retrieve word variants: the ((((double felix) or (double eyelid))) or (((double fusion) OR (double diffusion))))*.