Perhaps you should try some spelling variations:
theo chieu » theo tieu, ho chieu, theo chu
chieu sach » chinh sach, chiet tach, chieu sang
hanh tang » hanh trang, anh tang, hanh mang
va thong » va thuong, va phuong, va cong
cong tac » cong ty
tac toan » tap toan, tam toan, hach toan
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 chieu sach - hanh tang ((va thong) or (he thong)) cong tac toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo chieu sach - hanh tang ((va thong) OR (he thong)) cong tac toan cau.
• Adding a wildcard symbol may retrieve word variants: theo chieu sach - hanh tang ((va thong) or (he thong)) cong tac toan cau*.