Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
nhung cong » dung cong, thong cong, hang cong
theo hieu » theo chieu, theo tieu, thien hieu
thong cua » thong quan, thong tu, huong cua
hach toan » thanh toan, manh toan
mang cua » manh cua, dung cua, ban cua
tac toan » tap toan, tam toan, tich toan

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

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