Perhaps you should try some spelling variations:
nuoc sach » nguoi sach, cuoc cach, cuon sach
thanh tai » thanh hai, thanh toan, doanh tai
ban thanh » ban hanh, ban hang
hoc sach » hoc sinh, hoc cac, hoc anh
hieu cua » hieu qua, dieu cua, bieu cua
ca viet » co viet, hoa viet, san viet
va viet » hoa viet, san viet, mai viet
hang xa » hoang xa, hang va, hang ca
ty hang » ly hang, ty xang, thi hang
lo ban » co ban, lo van, ly ban
cac lo » cac lop, cac co, cac bo

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((nuoc sach) or (hoc sach)) ty hang xa hoi. hieu cua cac lo ban thanh tai ((ca viet) OR (va viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((nuoc sach) OR (hoc sach)) ty hang xa hoi. hieu cua cac lo ban thanh tai ((ca viet) OR (va viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((nuoc sach) or (hoc sach)) ty hang xa hoi. hieu cua cac lo ban thanh tai ((ca viet) OR (va viet))".
• Adding a wildcard symbol may retrieve word variants: ((nuoc sach) or (hoc sach)) ty hang xa hoi. hieu cua cac lo ban thanh tai ((ca viet) OR (va viet))*.