Perhaps you should try some spelling variations:
diffunction systemss » diffusion systems
function systems » equation systems, function spaces, fusion system
systemss based » system based
systems fast » systems a, systems game
based tools » based tool, coated 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 systems fast tools ) or ( diffunction systemss based tools ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( function systems fast tools ) OR ( diffunction systemss based tools )).
• Adding a wildcard symbol may retrieve word variants: (( function systems fast tools ) or ( diffunction systemss based tools ))*.