Perhaps you should try some spelling variations:
boi hoat » toi hoat, doi hoat, voi hoat
van hanh » van thanh, ban hanh, van anh
cac xuc » cam xuc, cac nuoc, chat xuc
boi hoa » bi hoa, toi hoat
xuc van » duc van, luc van, vuc van
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
lai hoi » dai hoi, lai hoa, lai roi
mai hoi » mai khoi, dai hoi, mai doi
ve cac » va cac, vien cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ky nang ((mai hoi) OR (lai hoi)). hieu ve cac xuc van hanh ((boi hoa) or (boi hoat)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky nang ((mai hoi) OR (lai hoi)). hieu ve cac xuc van hanh ((boi hoa) OR (boi hoat)) viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky nang ((mai hoi) OR (lai hoi)). hieu ve cac xuc van hanh ((boi hoa) or (boi hoat)) viet".
• Adding a wildcard symbol may retrieve word variants: so sach ky nang ((mai hoi) OR (lai hoi)). hieu ve cac xuc van hanh ((boi hoa) or (boi hoat)) viet*.