Perhaps you should try some spelling variations:
tieu sach » chieu sach, dien sach, te sach
anh nang » ganh nang, anh bang, anh dang
cong tan » cong tac, cong thanh, cong ty
cong san » cong tac
toan cau » toan cao, toan ban, toan tap
nang du » nang tu, nang luc, nang doc
du tung » duc tung, duy tung, yu tung

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 nang du tung ((cong tan) or (cong san)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo tieu sach - anh nang du tung ((cong tan) OR (cong san)) toan cau.
• Adding a wildcard symbol may retrieve word variants: theo tieu sach - anh nang du tung ((cong tan) or (cong san)) toan cau*.