Perhaps you should try some spelling variations:
theo hieu » theo chieu, theo tieu, thien hieu
hieu lang » chieu sang, hieu quang, nhieu tang
hanh nang » anh nang, ganh nang, hanh mang
dung cong » dung trong
dang toan » dan toan, dung toan, dang thanh
dang tran » dang thanh, quang tran, hoang tran
nang su » dang su, nang du, nang tu

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 lang - hanh nang su dung cong ((dang toan) or (dang tran)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo hieu lang - hanh nang su dung cong ((dang toan) OR (dang tran)) cau*.