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

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 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 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 tre*.