Perhaps you should try some spelling variations:
heats » cheats, heat, heads
hears » hearts, years, heart
speare » sheare, speake, spare
spear » shear, speak, spar
sheath » heath
solution » solutions

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: ((heats OR cham) OR ((hears OR (speare OR spear)) OR sheath)) of mixing AND solution.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((heats or cham) or ((hears or (speare OR spear)) or sheath)) of mixing and solution".
• Adding a wildcard symbol may retrieve word variants: ((heats or cham) or ((hears or (speare OR spear)) or sheath)) of mixing and solution*.