Perhaps you should try some spelling variations:
ty doanh » ly doanh, te doanh, tri doanh
xanh tai » hanh tai, anh tai, vanh tai
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
van hoi » van hoa, van hoe, van loi
van hoc » van hoa
hieu va » lieu va, hieu qua
cac luc » cau luc, cac nuoc, cac cuoc
va xanh » va danh, va hanh, va anh
cuc te » cua te, cuc thue, cuc tieu

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 ty doanh ((van hoi) OR (van hoc)). hieu va ((cac luc) or (coc luc)) va xanh tai cuc te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty doanh ((van hoi) OR (van hoc)). hieu va ((cac luc) OR (coc luc)) va xanh tai cuc te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty doanh ((van hoi) OR (van hoc)). hieu va ((cac luc) or (coc luc)) va xanh tai cuc te".
• Adding a wildcard symbol may retrieve word variants: tu sach ty doanh ((van hoi) OR (van hoc)). hieu va ((cac luc) or (coc luc)) va xanh tai cuc te*.