Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
lam duoc » nam duoc, luat duoc, lam thuoc
hieu van » hieu va, thien van, lieu va
ty hang » ly hang, ty xang, thi hang
ty lang » tay lang, ty xang, tu lang
duoc ma » duoc lam
ma hang » mat hang, mua hang, va hang
va chua » vua chua, va chu, a chua
ca chua » ca cua, sua chua
van lam » van nam

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ((ty lang) or (ty hang)) xa hoi. hieu van lam duoc ma hang ((va chua) OR (ca chua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ty lang) OR (ty hang)) xa hoi. hieu van lam duoc ma hang ((va chua) OR (ca chua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((ty lang) or (ty hang)) xa hoi. hieu van lam duoc ma hang ((va chua) OR (ca chua)) tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ((ty lang) or (ty hang)) xa hoi. hieu van lam duoc ma hang ((va chua) OR (ca chua)) tre*.