Perhaps you should try some spelling variations:
dua tren » dung tren
hang tai » hang va, dung tai
nam thuc » nam thuoc, am thuc, nam thu
cao hoc » co hoc, cho hoc, chat hoc
lieu ha » lieu nha, lieu va, liem ha
thuc va » thuc vat, thuc dan, thuc day
va hang » van hang, va nang, va lang
cao hoi » cau hoi, co hoi, tao hoi
cu tren » tu tren
sac ky » cac ky, sai ky
tu sac » tu sach, tu cac, tu san

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky nang ((cao hoi) or (cao hoc)). lieu ha nam thuc va hang tai ((cu tren) OR (dua tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky nang ((cao hoi) OR (cao hoc)). lieu ha nam thuc va hang tai ((cu tren) OR (dua tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky nang ((cao hoi) or (cao hoc)). lieu ha nam thuc va hang tai ((cu tren) OR (dua tren))".
• Adding a wildcard symbol may retrieve word variants: tu sac ky nang ((cao hoi) or (cao hoc)). lieu ha nam thuc va hang tai ((cu tren) OR (dua tren))*.