Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
cua viet » ca viet, hoa viet, cua vat
hieu van » hieu va, thien van, lieu va
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
so sanh » do sanh
mai hoi » mai khoi, dai hoi, lai hoi
dai hai » dai han, dai hoi, dai tai
hieu ve » hieu va
sanh v » sanh va, canh v, sanh _
v nang » va nang, vu nang, van nang
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sanh v nang ((mai hoi) or (dai hai)). ((hieu ve) OR (hieu van)) cham thuc va hanh vi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sanh v nang ((mai hoi) OR (dai hai)). ((hieu ve) OR (hieu van)) cham thuc va hanh vi cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sanh v nang ((mai hoi) or (dai hai)). ((hieu ve) OR (hieu van)) cham thuc va hanh vi cua viet".
• Adding a wildcard symbol may retrieve word variants: so sanh v nang ((mai hoi) or (dai hai)). ((hieu ve) OR (hieu van)) cham thuc va hanh vi cua viet*.