Perhaps you should try some spelling variations:
hoc thuyet » hoc chuyen
canh trinh » canh tranh, hanh trinh, canh tinh
dung cong » dung trong
trinh va » trinh van, trinh vat, trinh ve
cong tan » cong tac, cong san, cong thanh
va dung » van dung, va duong, vat dung
tan van » tran van, tang van, luan van
van cau » van dau, van hau, van chat

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((hoc hien) or (hoc thuyet)) anh - canh trinh va dung cong tan van cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc hien) OR (hoc thuyet)) anh - canh trinh va dung cong tan van cau.
• Adding a wildcard symbol may retrieve word variants: ((hoc hien) or (hoc thuyet)) anh - canh trinh va dung cong tan van cau*.