Perhaps you should try some spelling variations:
thieu khang » chieu khong, thieu quang
thieu sang » chieu sang, thieu quang, hieu lang
hanh trung » thanh trung, hanh trang, manh trung
cap hang » cap hoang, cap han, cau thang
cap bang » cao bang, can bang, lap bang
cong dan » cong san, cong tan, huong dan
dan toan » van toan, dan than, manh toan
toan cao » toan ban, toan tap

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 trung ((cap hang) OR (cap bang)) cong dan toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sang) OR (thieu khang)) - hanh trung ((cap hang) OR (cap bang)) cong dan toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sang) or (thieu khang)) - hanh trung ((cap hang) OR (cap bang)) cong dan toan cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sang) or (thieu khang)) - hanh trung ((cap hang) OR (cap bang)) cong dan toan cao*.