Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
hanh tranh » canh tranh, hanh trinh, hanh trang
tranh cua » doanh cua, manh cua
cua trong » cua truong, cua trung, qua trong
hoc hieu » hoc thieu, hoc hien, doc hieu
san toan » van toan, manh toan, xuan toan
dan toan » van toan, dan than, manh 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 hieu quang - hanh tranh cua trong cong ((san toan) or (dan toan)) tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu quang - hanh tranh cua trong cong ((san toan) OR (dan toan)) tap.
• Adding a wildcard symbol may retrieve word variants: hoc hieu quang - hanh tranh cua trong cong ((san toan) or (dan toan)) tap*.