Perhaps you should try some spelling variations:
su triet » su tien, ve triet
tu sach » thu sach, su sach, te sach
ban dan » ban hang, ban hanh, ban quan
duc ban » duc tan, duc van, dua ban
cam duc » cam xuc, cao duc, pham duc
nang ma » sang ma, nang cao, mang may
tang ma » mang may, tang van
su viet » so viet
va cam » va cham, va cac, va cao
dan vi » doan vi, don vi, dan 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 y ((nang ma) OR (tang ma)) hoi. lieu va cam duc ban dan vi ((su triet) or (su viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((nang ma) OR (tang ma)) hoi. lieu va cam duc ban dan vi ((su triet) OR (su viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((nang ma) OR (tang ma)) hoi. lieu va cam duc ban dan vi ((su triet) or (su viet))".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang ma) OR (tang ma)) hoi. lieu va cam duc ban dan vi ((su triet) or (su viet))*.