Perhaps you should try some spelling variations:
thanh trung » thanh tung
chieu sang » chieu sach, chieu xanh, hieu lang
nhung cong » dung cong, thong cong, hang cong
hieu manh » chieu xanh, hieu nganh, dieu hanh
trung va » truong va, trang va, trung ha
cong tan » cong tac, cong san, cong thanh
toan ban » van ban

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

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu manh) OR (chieu sang)) - thanh trung va nhung cong tan ((toan tap) OR (toan ban))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hieu manh) or (chieu sang)) - thanh trung va nhung cong tan ((toan tap) OR (toan ban))~".
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu manh) or (chieu sang)) - thanh trung va nhung cong tan ((toan tap) OR (toan ban))*.