Perhaps you should try some spelling variations:
hieu lang » chieu sang, hieu quang, nhieu tang
hanh manh » hanh mang, lanh manh, hoang manh
hach toan » thanh toan, manh toan
hoc hieu » hoc thieu, hoc hien, doc hieu
cua dang » cua cong, cua ban
qua dung » quang dung, su dung, qua song
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: hoc hieu lang - hanh manh ((cua dang) or (qua dung)) cong ((tac toan) or (hach toan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu lang - hanh manh ((cua dang) OR (qua dung)) cong ((tac toan) OR (hach toan)) cau.
• Adding a wildcard symbol may retrieve word variants: hoc hieu lang - hanh manh ((cua dang) or (qua dung)) cong ((tac toan) or (hach toan)) cau*.