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

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 - ((hanh han) OR (hanh san)) 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 - ((hanh han) OR (hanh san)) 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 - ((hanh han) OR (hanh san)) va phuong cong ((van tuan) or (ban hanh)) ban".
• Adding a wildcard symbol may retrieve word variants: hoc hieu lang - ((hanh han) OR (hanh san)) va phuong cong ((van tuan) or (ban hanh)) ban*.