Perhaps you should try some spelling variations:
hieu quan » hieu qua, lieu quan, thien quan
hay lang » ha lang, nhan lang, phap lang
tay lang » tai lang, tay tang, tay quang
tu sach » thu sach, su sach, te sach
va hanh » van hanh, va thanh, va danh
va phuc » van phuc, va thuc, xa phuc
quan va » quan vi, quan ha, luan va
vi cua » vai cua, di cua
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ((hay lang) OR (tay lang)) xa hoi. hieu quan va phuc ((va hanh) or (dia ban)) vi cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((hay lang) OR (tay lang)) xa hoi. hieu quan va phuc ((va hanh) OR (dia ban)) vi cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((hay lang) OR (tay lang)) xa hoi. hieu quan va phuc ((va hanh) or (dia ban)) vi cua tu".
• Adding a wildcard symbol may retrieve word variants: tu sach ((hay lang) OR (tay lang)) xa hoi. hieu quan va phuc ((va hanh) or (dia ban)) vi cua tu*.