Perhaps you should try some spelling variations:
vay doanh » van doanh, ly doanh, voi doanh
lang van » tang van, hoang van, giang van
dang van » hoang van, hang va
te sach » toc sach
sach tu » sach thu, cach tu, sach ty
qua cao » qua cac, qua ca, qua cai
cao duc » dao duc, cao suc, giao duc
duc vay » duc va, duc van, duc vy
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach tu ((mang may) or (((lang van) or (dang van)))) hoi. hieu qua cao duc vay doanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach tu ((mang may) OR (((lang van) OR (dang van)))) hoi. hieu qua cao duc vay doanh tai cua tre.
• Adding a wildcard symbol may retrieve word variants: te sach tu ((mang may) or (((lang van) or (dang van)))) hoi. hieu qua cao duc vay doanh tai cua tre*.