Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
lieu van » lieu va, hieu van, sieu van
van pham » san pham, van phan, van phat
van hanh » van thanh, ban hanh, van anh
hanh dai » hanh tai, hanh dao, vanh dai
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
duc van » duc va, duc tan, duc manh
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu hoach) or (((tu sach) OR (su sach)))) ky nang o hoi. lieu van pham duc van hanh dai cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu hoach) OR (((tu sach) OR (su sach)))) ky nang o hoi. lieu van pham duc van hanh dai cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu hoach) or (((tu sach) OR (su sach)))) ky nang o hoi. lieu van pham duc van hanh dai cua triet".
• Adding a wildcard symbol may retrieve word variants: ((thu hoach) or (((tu sach) OR (su sach)))) ky nang o hoi. lieu van pham duc van hanh dai cua triet*.