Perhaps you should try some spelling variations:
phung cong » nhung cong, phong cong, nhung chong
hieu lang » chieu sang, hieu quang, nhieu tang
hanh dang » hanh dong, hanh dung, hanh mang
hung cong » nhung cong, hung cuong, dung cong
anh dang » anh dong, anh dung, anh bang
tac toan » tap toan, tam toan, hach toan
toan ban » van ban
ho hieu » ho chieu, hoi hieu, nho hieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ho hieu lang - ((hanh dang) or (anh dang)) luan ((hung cong) OR (phung cong)) tac toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho hieu lang - ((hanh dang) OR (anh dang)) luan ((hung cong) OR (phung cong)) tac toan ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho hieu lang - ((hanh dang) or (anh dang)) luan ((hung cong) OR (phung cong)) tac toan ban".
• Adding a wildcard symbol may retrieve word variants: ho hieu lang - ((hanh dang) or (anh dang)) luan ((hung cong) OR (phung cong)) tac toan ban*.