Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
su triet » su viet, su tien, ve triet
su sach » so sach, vu sach
tang ma » tang van
hieu va » lieu va, hieu qua
cac tuc » cac toc, cac tu, cac tac
va hanh » van hanh, va thanh, va danh
vai su » va su, van su, lai su

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach y ((tang ma) OR (mang may)) hoa. hieu va cac tuc ((va hanh) or (ban thanh)) vai su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((tang ma) OR (mang may)) hoa. hieu va cac tuc ((va hanh) OR (ban thanh)) vai su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y ((tang ma) OR (mang may)) hoa. hieu va cac tuc ((va hanh) or (ban thanh)) vai su triet".
• Adding a wildcard symbol may retrieve word variants: su sach y ((tang ma) OR (mang may)) hoa. hieu va cac tuc ((va hanh) or (ban thanh)) vai su triet*.