Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
trinh cua » trinh luat, trinh quan, trinh luan
tranh cua » doanh cua, manh cua
dung cong » dung trong
hoi hieu » hoi phieu, hoi tieu, moi hieu
tinh cua » sinh cua, tinh chat, tinh thua
cong tap » cuong tap, cong tac, cong tan
tap toan » tap doan, tap quan, bai toan
toan cao » toan ban, toan tap

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

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