Perhaps you should try some spelling variations:
hieu lang » chieu sang, hieu quang, nhieu tang
trinh san » trinh han, trinh quan, trinh toan
dung cong » dung trong
trinh su » trinh tu, trinh cau, trinh cua
tap toan » tap doan, bai toan
tap quan » tac quan, hai quan
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 ((trinh su) OR (trinh san)) dung cong ((tap toan) or (tap quan)) cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho hieu lang - hanh ((trinh su) OR (trinh san)) dung cong ((tap toan) OR (tap quan)) cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho hieu lang - hanh ((trinh su) OR (trinh san)) dung cong ((tap toan) or (tap quan)) cao".
• Adding a wildcard symbol may retrieve word variants: ho hieu lang - hanh ((trinh su) OR (trinh san)) dung cong ((tap toan) or (tap quan)) cao*.