Perhaps you should try some spelling variations:
hieu quan » lieu quan, thien quan, lien quan
ban hanh » ban hang
su sach » so sach, vu sach
lang xa » lang ha, dang xay, lang van
va danh » va dinh, va dan, va hanh
vai hoa » van hoa, va hoa, dai hoa
sach o » sach lo, sac o, sach y
o lang » hoa lang, hoi lang
nam tu » nam thu, nam thuc

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach o lang xa hoi. ((hieu qua) or (hieu quan)) nam tu ((va danh) or (ban hanh)) vai hoa viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach o lang xa hoi. ((hieu qua) OR (hieu quan)) nam tu ((va danh) OR (ban hanh)) vai hoa viet.
• Adding a wildcard symbol may retrieve word variants: su sach o lang xa hoi. ((hieu qua) or (hieu quan)) nam tu ((va danh) or (ban hanh)) vai hoa viet*.