Perhaps you should try some spelling variations:
thieu sach » chieu sach, thien hach, hieu cach
hanh trang » thanh trung, hanh trinh, minh trang
hoc thieu » toc thieu, hoc hien
dung cong » dung trong
cong san » cong tac
san toan » van toan, dan toan, manh 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: hoc thieu sach - ((hanh trang) or (canh tranh)) su dung cong san toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thieu sach - ((hanh trang) OR (canh tranh)) su dung cong san toan cau.
• Adding a wildcard symbol may retrieve word variants: hoc thieu sach - ((hanh trang) or (canh tranh)) su dung cong san toan cau*.