Perhaps you should try some spelling variations:
chiet tach » chieu sach
hanh trang » thanh trung, canh tranh, hanh trinh
nhung cong » dung cong, thong cong, hang cong
hoc chiet » hoc thiet, hoc nhiet, hoc hien
trang cua » tranh cua, tang cua, trung cua
cua nhung » va nhung
tan toan » tan tran, dan toan, tam toan
van toan » van tuan, van tan, van thanh
tap toan » tap doan, tap quan, bai toan

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

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