Perhaps you should try some spelling variations:
tran thanh » ban thanh, van thanh, quan thanh
hieu manh » chieu xanh, hieu nganh, dieu hanh
tran tuan » tran xuan, tranh luan, tran van
dung cong » dung trong
hoc hieu » hoc thieu, hoc hien, doc hieu
cong tac » cong ty
tac toan » tap toan, tam toan, hach toan
toan cau » toan cao, toan ban, toan tap

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 - thanh ((((tran tuan) OR (tran quang))) OR (tran thanh)) dung cong tac toan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu manh - thanh ((((tran tuan) OR (tran quang))) or (tran thanh)) dung cong tac toan cau~".
• Adding a wildcard symbol may retrieve word variants: hoc hieu manh - thanh ((((tran tuan) OR (tran quang))) or (tran thanh)) dung cong tac toan cau*.