Perhaps you should try some spelling variations:
chat triet » chet triet, chat thien, cua triet
thanh lam » thanh lap, hanh lam, thanh nam
van thanh » ban thanh, van tuan
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
dau duc » dao duc, dang duc, dau nuoc
duc van » duc va, duc tan, duc manh
co hoi » co hoc, co loi
va dau » va dao
o hoi » o hoc, o hai, o hoa
phat » phan, pham, phap

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