Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
trinh quan » tinh quang, trinh luat, trinh han
thong dung » thong cong, thong thuong
trinh cua » tinh cua, trinh luat, trinh luan
thong cua » thong quan, thong tu, huong cua
doi hieu » doi chieu, doc hieu, doi hien
toan tap » toan ban

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

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