Perhaps you should try some spelling variations:
diffusion systems » fusion system
function system » function systems, fusion system
systems based » system based, systems fast, systems game
system a » system _, systems _
based co » based code, based no2, based two
a tools » a tool, _ tools

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( function system a tools ) or ( diffusion systems based co ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( function system a tools ) OR ( diffusion systems based co )).
• Adding a wildcard symbol may retrieve word variants: (( function system a tools ) or ( diffusion systems based co ))*.