Perhaps you should try some spelling variations:
thanh ve » hanh ve, thanh va, thanh vien
thanh vi » hanh vi, thanh va, nhanh vi
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
qua coc » qua cac, qua co, qua con
ky lang » ky nang, ky dang, ky tang
cua tre » cua te, cuu tre, cua triet
luc va » duc va, tuc va, loc va
ha hoi » hoa hoi, ha noi, va hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky lang ((ha hoi) or (xa hoi)). hieu qua coc luc va ((thanh vi) OR (thanh ve)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky lang ((ha hoi) OR (xa hoi)). hieu qua coc luc va ((thanh vi) OR (thanh ve)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky lang ((ha hoi) or (xa hoi)). hieu qua coc luc va ((thanh vi) OR (thanh ve)) cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky lang ((ha hoi) or (xa hoi)). hieu qua coc luc va ((thanh vi) OR (thanh ve)) cua tre*.