Perhaps you should try some spelling variations:
nhiet tach » chiet tach
hanh trinh » canh tranh, hanh chinh
quan thong » quang thong, xuan thong, quang thang
quan trong » gian trong
hoc nhiet » hoc thiet, hoc nghien, hoc hien
cong san » cong tac
san than » sang than, san thanh, ban than
than ban » thanh ban, toan ban, than man

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc nhiet tach - hanh trinh ((quan thong) OR (quan trong)) cong san than ban~".
• Adding a wildcard symbol may retrieve word variants: hoc nhiet tach - hanh trinh ((quan thong) OR (quan trong)) cong san than ban*.