Perhaps you should try some spelling variations:
dau tren » dau tien, dat tren, dau tieng
thanh ve » hanh ve, thanh va, thanh vien
va thanh » gia thanh, ban thanh, va tinh
cua tre » cua te, cuu tre, cua triet
cam duc » cam xuc, cao duc, pham duc
sach ky » sac ky, sach y, sach ty
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
ve cam » ve cham, ve cac, va cam
o hai » co hai, so hai, o lai
o hoi » co hoi, o hoc, o hoa

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 nang ((o hoi) OR (o hai)). hieu ve cam duc va thanh ve ((cua tre) or (dau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ((o hoi) OR (o hai)). hieu ve cam duc va thanh ve ((cua tre) OR (dau tren))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ((o hoi) OR (o hai)). hieu ve cam duc va thanh ve ((cua tre) or (dau tren))*".