Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
sach thu » sach thue, sach thieu, sach tham
thu nang » thi nang, thu hang, thu bang
nang lai » nang tai, mang lai, nang cai
van vat » van chat, nhan vat
dan vat » dang vat, dan va, dan dat
tu sach » thu sach, su sach, te sach
lai roi » lai hoi, loi roi
hieu va » hieu qua
co duc » co duoc, cao duc, do duc

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 thu nang lai roi. ((hieu va) or (lieu va)) co duc va ((dan vat) OR (van vat)) va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thu nang lai roi. ((hieu va) OR (lieu va)) co duc va ((dan vat) OR (van vat)) va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach thu nang lai roi. ((hieu va) or (lieu va)) co duc va ((dan vat) OR (van vat)) va triet".
• Adding a wildcard symbol may retrieve word variants: tu sach thu nang lai roi. ((hieu va) or (lieu va)) co duc va ((dan vat) OR (van vat)) va triet*.