Perhaps you should try some spelling variations:
xuan truong » xa truong, duong truong
hanh trang » thanh trung, canh tranh, hanh trinh
cua trong » cua truong, cua trung, qua trong
hieu luc » hieu luat
cong san » cong tac
san tan » van tan, san van, san tay
tan tap » toan tap, han tap, tan tat

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((hieu luc) or (hieu qua)) - hanh trang ((cua trong) or (xuan truong)) cong san tan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu luc) OR (hieu qua)) - hanh trang ((cua trong) OR (xuan truong)) cong san tan tap.
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu luc) or (hieu qua)) - hanh trang ((cua trong) or (xuan truong)) cong san tan tap*.