Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
thu sach » thuat sach, thuoc sach, thu hoach
thu mang » thu hang, thu bang, thu dang
mang lai » mang lam, mang luoi, dang loai
dan vat » dang vat, van vat, dan va
tu sach » su sach, te sach, tu cach
lai roi » lai hoi, loi roi
hieu va » hieu qua
co duc » co duoc, cao duc, do duc
va dan » ca dan, va dao, va dau
vat va » dat va

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