Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
nhung cong » dung cong, thong cong, nhung don
biet cach » bien canh, viet sach, bien cac
hanh hang » thanh hang, hang hang, hanh han
hang cong » dang cong, hang nong, bang cong
van toan » van tuan, van tan, van thanh
toan cau » toan cao, toan ban, toan tap
hang ca » hang va, nang cao, hang tai

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((biet cach) or (chieu sach)) - hanh hang ca ((nhung cong) OR (hang cong)) van toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((biet cach) OR (chieu sach)) - hanh hang ca ((nhung cong) OR (hang cong)) van toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((biet cach) or (chieu sach)) - hanh hang ca ((nhung cong) OR (hang cong)) van toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((biet cach) or (chieu sach)) - hanh hang ca ((nhung cong) OR (hang cong)) van toan cau*.