Perhaps you should try some spelling variations:
trung thanh » truong thanh
chieu sang » chieu sach, chieu xanh, hieu lang
manh trung » manh tung, thanh trung, manh hung
quang toan » quang tuan, quang tran, quang doan
hien sang » hien trang, khien bang, thien bang
hang dong » hang nong, hanh dong, lang dong
hang cong » dang cong, hang nong, bang cong
toan cau » 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 ((hien sang) OR (chieu sang)) - manh trung thanh ((hang dong) or (hang cong)) quang toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hien sang) OR (chieu sang)) - manh trung thanh ((hang dong) OR (hang cong)) quang toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hien sang) OR (chieu sang)) - manh trung thanh ((hang dong) or (hang cong)) quang toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((hien sang) OR (chieu sang)) - manh trung thanh ((hang dong) or (hang cong)) quang toan cau*.