Perhaps you should try some spelling variations:
tieu sach » chieu sach, dien sach, te sach
anh tang » anh bang, anh dang, anh nang
tang duy » tang du, tang quy, tung duy
duy dung » duc dung, duy hung, duy tung
cong tan » cong thanh, cong ty, cong ha
cong tac » cong ty
toan cau » toan cao, toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: theo tieu sach - anh tang duy dung ((((cong tan) OR (cong tac))) or (cong san)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo tieu sach - anh tang duy dung ((((cong tan) OR (cong tac))) OR (cong san)) toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo tieu sach - anh tang duy dung ((((cong tan) OR (cong tac))) or (cong san)) toan cau".
• Adding a wildcard symbol may retrieve word variants: theo tieu sach - anh tang duy dung ((((cong tan) OR (cong tac))) or (cong san)) toan cau*.