Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van pham » san pham, van phan, van phat
va thanh » gia thanh, ban thanh, va tinh
thanh do » thanh de, thanh pho, thanh hoa
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
cua tre » cua te, cuu tre, cua triet
co hoi » co hoc, co loi
do cua » doi cua, co cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang ((co hoi) or (cau hoi)). hieu van pham duc va thanh do cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((co hoi) OR (cau hoi)). hieu van pham duc va thanh do cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((co hoi) or (cau hoi)). hieu van pham duc va thanh do cua tre*.