Perhaps you should try some spelling variations:
phuong cong » phuong dong, phong cong, phung cong
chieu sang » chieu sach, chieu xanh, nhieu tang
hieu lang » hieu quang, nhieu tang, hieu van
va phuong » va thuong, cac phuong
hanh han » hanh nhan, hanh phan, hanh san
van tuan » van quan, van ban, anh tuan
ban hanh » ban hang
han va » hang va, hanh va, nhan va

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