Perhaps you should try some spelling variations:
thuyet mach » thuyet xac, thuyet cac, thuyet anh
hoc thuyet » hoc chuyen
hanh trinh » canh tranh, hanh chinh
trinh xuan » trinh quan, trinh luan, trinh luat
xuan trong » xuan truong, quan trong, xuan trung
dan than » dan chan, van than, dan toan
ban than » ban thanh, van thanh, 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 thuyet mach - hanh trinh xuan trong cong ((dan than) or (ban than)) man~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thuyet mach - hanh trinh xuan trong cong ((dan than) OR (ban than)) man.
• Adding a wildcard symbol may retrieve word variants: hoc thuyet mach - hanh trinh xuan trong cong ((dan than) or (ban than)) man*.