Perhaps you should try some spelling variations:
tieu sach » chieu sach, dien sach, te sach
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
anh van » anh va, thanh van, doanh van
van duy » van dung

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 van 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 van duy dung ((((cong tan) OR (cong tac))) OR (cong san)) toan cau.
• Adding a wildcard symbol may retrieve word variants: theo tieu sach - anh van duy dung ((((cong tan) or (cong tac))) or (cong san)) toan cau*.