Perhaps you should try some spelling variations:
thieu khang » chieu khong, thieu quang
thieu sang » chieu sang, thieu quang, hieu lang
trinh cuan » trinh chuan, trinh quan, trinh luan
thong cong » trong cong, tong cong, thong thong
trinh cua » tinh cua, trinh luat, trinh quan
cong san » cong tac
san toan » van toan, dan toan, manh toan
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 ((thieu sang) OR (thieu khang)) - hanh ((trinh cua) or (trinh cuan)) thong cong san toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sang) OR (thieu khang)) - hanh ((trinh cua) OR (trinh cuan)) thong cong san toan ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sang) OR (thieu khang)) - hanh ((trinh cua) or (trinh cuan)) thong cong san toan ban".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sang) OR (thieu khang)) - hanh ((trinh cua) or (trinh cuan)) thong cong san toan ban*.