Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
van hanh » van thanh, ban hanh, van anh
hanh lai » hanh lam, hanh tai, thanh lap
tu sach » thu sach, su sach, te sach
sach tu » sach thu, cach tu, sach ty
tu nang » tru nang, tu nong, tu nano
hieu ve » hieu va, hieu van
cac luc » cau luc, coc luc, cac nuoc
luc van » luoc van, luu van, duc van
cua tre » cua te, cuu tre, dua tren
ve cac » va cac, vien cac
x hoi » xa hoi, o hoi, 5 hoi

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 tu nang ((x hoi) OR (x ho)). hieu ve cac luc van hanh lai ((cua tre) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach tu nang ((x hoi) OR (x ho)). hieu ve cac luc van hanh lai ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach tu nang ((x hoi) OR (x ho)). hieu ve cac luc van hanh lai ((cua tre) or (cua triet))".
• Adding a wildcard symbol may retrieve word variants: tu sach tu nang ((x hoi) OR (x ho)). hieu ve cac luc van hanh lai ((cua tre) or (cua triet))*.