Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
trinh qua » trinh quan, trinh quang, trinh luat
trinh cua » tinh cua, trinh luat, trinh quan
ban cong » bang cong, van cong, phan cong
cong tai » cong thai, cong tac, dong tai
tren tau » tren thuc, tren dat, tren thi
tren may » tiet may
ho hieu » ho chieu, hoi hieu, nho hieu

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ho hieu quang - hanh ((trinh qua) OR (trinh cua)) ban cong tai ((tren tau) OR (tren may))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho hieu quang - hanh ((trinh qua) or (trinh cua)) ban cong tai ((tren tau) OR (tren may))~".
• Adding a wildcard symbol may retrieve word variants: ho hieu quang - hanh ((trinh qua) or (trinh cua)) ban cong tai ((tren tau) OR (tren may))*.