Perhaps you should try some spelling variations:
cua triet » cua viet, su triet
thu sach » thuat sach, thuoc sach, thu hoach
hanh dai » hanh tai, hanh dao, vanh dai
van hanh » van thanh, ban hanh, van anh
van pham » san pham, van phan, van phat
lieu van » lieu va, hieu van, sieu van
va triet » va thiet, va trien, ve triet
duc van » duc va, duc tan, duc manh
tu sach » su sach, te sach, tu cach
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 sach) or (tu sach)) ky nang o hoi. lieu van pham duc van hanh dai ((cua triet) OR (va triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (tu sach)) ky nang o hoi. lieu van pham duc van hanh dai ((cua triet) OR (va triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (tu sach)) ky nang o hoi. lieu van pham duc van hanh dai ((cua triet) OR (va triet))".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (tu sach)) ky nang o hoi. lieu van pham duc van hanh dai ((cua triet) OR (va triet))*.