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

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)). thien van pham duc va thanh di ((cua tre) OR (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((co hoi) OR (cau hoi)). thien van pham duc va thanh di ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((co hoi) or (cau hoi)). thien van pham duc va thanh di ((cua tre) OR (cua triet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((co hoi) or (cau hoi)). thien van pham duc va thanh di ((cua tre) OR (cua triet))*.