Perhaps you should try some spelling variations:
thanh trung » thanh tung
vien thanh » viet thanh, dien thanh, thien thanh
tien thanh » tien thinh, tran thanh, den thanh
cong trong » cong thuong, duong trong, cong trinh
hieu xanh » chieu xanh, hieu manh, hieu nganh
trung cua » truong cua, trung tuan, trung cap
khoan ban » khoan bai, khoan danh, khoan quan

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc ((hieu xanh) or (((vien thanh) OR (tien thanh)))) - thanh trung cua cong trong cac khoan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu xanh) OR (((vien thanh) OR (tien thanh)))) - thanh trung cua cong trong cac khoan ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu xanh) or (((vien thanh) OR (tien thanh)))) - thanh trung cua cong trong cac khoan ban".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu xanh) or (((vien thanh) OR (tien thanh)))) - thanh trung cua cong trong cac khoan ban*.