Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
chat loc » chat hoc, chat doc, chat long
sach ky » sac ky, sach y, sach ty
cua tre » cua te, cuu tre, dua tren
hanh le » thanh le, hanh ve, hanh de
va hanh » van hanh, va thanh, va danh
te sach » toc sach
hieu va » lieu va, hieu qua
dai hoi » dai hoc, dai hai, dai moi
mai hoi » mai khoi, lai hoi, mai doi
va chat » van chat, va phat, cao chat
loc va » hoc va, luc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky nang ((mai hoi) OR (dai hoi)). hieu va chat loc va hanh le ((cua tre) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang ((mai hoi) OR (dai hoi)). hieu va chat loc va hanh le ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky nang ((mai hoi) OR (dai hoi)). hieu va chat loc va hanh le ((cua tre) or (cua triet))".
• Adding a wildcard symbol may retrieve word variants: te sach ky nang ((mai hoi) OR (dai hoi)). hieu va chat loc va hanh le ((cua tre) or (cua triet))*.