Perhaps you should try some spelling variations:
thieu sang » thieu khang, thieu quang, hieu lang
chieu sang » chieu sach, chieu xanh, hieu lang
hanh trung » thanh trung, hanh trang, manh trung
trung cua » truong cua, trung tuan, trung cap
hang cong » dang cong, hang nong, thanh cong
bang cong » dang cong, bang song, dung cong
tac than » tac thanh, tam than, tac nhan
than tap » toan tap, han tap, phan 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 (chieu sang)) - hanh trung cua ((hang cong) OR (bang cong)) tac than tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sang) OR (chieu sang)) - hanh trung cua ((hang cong) OR (bang cong)) tac than tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sang) or (chieu sang)) - hanh trung cua ((hang cong) OR (bang cong)) tac than tap".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sang) or (chieu sang)) - hanh trung cua ((hang cong) OR (bang cong)) tac than tap*.