Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, diep quang
thong cong » trong cong, tong cong, thong thong
hanh hang » thanh hang, hang hang, hanh han
va thong » va thuong, va phuong, he thong
cong van » cong vang, cong san, song van
toan cau » toan cao, toan tap, toan tai
toan ban » van ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((hieu quang) or (hieu qua)) - hanh hang va thong cong van ((toan cau) or (toan ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu quang) OR (hieu qua)) - hanh hang va thong cong van ((toan cau) OR (toan ban)).
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu quang) or (hieu qua)) - hanh hang va thong cong van ((toan cau) or (toan ban))*.