Perhaps you should try some spelling variations:
ve triet » va trien, su triet
chat doc » chat hoc, chau doc, thuat doc
chat duc » chat xuc, chet duoc, pham duc
tinh vi » trinh vi, tinh voi, tinh va
va tinh » may tinh
sach ky » sac ky, sach y, sach ty
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
o hai » co hai, so hai, o lai
o hoi » co hoi, o hoc, o hoa
vi ve » va ve, gi ve, ve ve

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