Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
hieu quan » lieu quan, thien quan, lien quan
cau tren » cu tren, dau tren, ca tren
thanh vi » hanh vi, thanh va, thanh ve
sach tu » sach thu, cach tu, sach ty
cua tre » cua te, cuu tre, cua triet
duc ban » duc tan, duc van, dua ban
vu sach » vu bach, su sach, vu khach
nang xa » nang x, lang xa, nang ma
tu nang » tru nang, tu nong, tu nano
dao duc » giao duc, tao duoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach tu nang xa hoi. ((hieu quan) or (hieu qua)) dao duc ban thanh vi ((cua tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach tu nang xa hoi. ((hieu quan) OR (hieu qua)) dao duc ban thanh vi ((cua tre) OR (cau tren)).
• Adding a wildcard symbol may retrieve word variants: vu sach tu nang xa hoi. ((hieu quan) or (hieu qua)) dao duc ban thanh vi ((cua tre) or (cau tren))*.