Perhaps you should try some spelling variations:
thieu quang » hieu quang, thien quan, trien quang
thieu sang » chieu sang, thieu khang, hieu lang
hanh han » hanh nhan, hanh phan, hanh san
cong dan » cong tan, huong dan, cong dong
cong san » cong tac
nhan tai » hang tai, van tai, toan tai
va tong » va thong, va tuong, va trong
han va » hang va, hanh va, nhan va

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 quang)) - hanh han va tong ((cong dan) OR (cong san)) nhan tai~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sang) OR (thieu quang)) - hanh han va tong ((cong dan) OR (cong san)) nhan tai.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sang) or (thieu quang)) - hanh han va tong ((cong dan) OR (cong san)) nhan tai".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sang) or (thieu quang)) - hanh han va tong ((cong dan) OR (cong san)) nhan tai*.