Perhaps you should try some spelling variations:
hien hanh » dieu hanh
hanh tang » hanh trang, anh tang, hanh mang
tang luan » dung luan
hung cong » nhung cong, hung cuong, phung cong
dung cong » dung trong
than cao » toan cao, thai cao, than sao
than cap » khan cap, thanh lap, thanh cac

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 hien hanh - hanh tang luan ((hung cong) OR (dung cong)) ban ((than cao) OR (than cap))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hien hanh - hanh tang luan ((hung cong) or (dung cong)) ban ((than cao) OR (than cap))~".
• Adding a wildcard symbol may retrieve word variants: hoc hien hanh - hanh tang luan ((hung cong) or (dung cong)) ban ((than cao) OR (than cap))*.