Perhaps you should try some spelling variations:
hieu nganh » vien nganh, hiem ngan, hieu manh
chieu sang » chieu sach, chieu xanh, hieu lang
manh trung » manh tung, thanh trung, manh hung
trung cua » truong cua, trung tuan, trung cap
cong dan » cong san, cong tan, cong dong
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 ((hieu nganh) or (chieu sang)) - manh trung cua ban ((cong dan) OR (huong dan)) toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu nganh) OR (chieu sang)) - manh trung cua ban ((cong dan) OR (huong dan)) toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hieu nganh) or (chieu sang)) - manh trung cua ban ((cong dan) OR (huong dan)) toan cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu nganh) or (chieu sang)) - manh trung cua ban ((cong dan) OR (huong dan)) toan cao*.