Perhaps you should try some spelling variations:
thanh vi » hanh vi, thanh va, thanh ve
va thanh » gia thanh, ban thanh, va tinh
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va
ky lang » ky nang, ky dang, ky tang
cua tre » cua te, cuu tre, cua triet
ha hoi » hoa hoi, ha noi, va hoi
luc va » duc va, tuc va, loc va
vi cua » vai cua, di cua

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 va) OR (hieu qua)) coc luc va thanh vi 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 va) OR (hieu qua)) coc luc va thanh vi 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 va) OR (hieu qua)) coc luc va thanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky lang ((ha hoi) or (xa hoi)). ((hieu va) OR (hieu qua)) coc luc va thanh vi cua tre*.