Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
nhung cong » dung cong, thong cong, hang cong
hieu manh » chieu xanh, hieu nganh, dieu hanh
trong van » trong cac
tang van » dang van, hoang van, tang luan
cong tan » cong tac, cong san, cong thanh
tran cau » tran chau, toan cau, ran cau

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: theo ((hieu manh) or (chieu sach)) - hanh ((tang van) OR (trong van)) nhung cong tan tran cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo ((hieu manh) OR (chieu sach)) - hanh ((tang van) OR (trong van)) nhung cong tan tran cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo ((hieu manh) or (chieu sach)) - hanh ((tang van) OR (trong van)) nhung cong tan tran cau".
• Adding a wildcard symbol may retrieve word variants: theo ((hieu manh) or (chieu sach)) - hanh ((tang van) OR (trong van)) nhung cong tan tran cau*.