Perhaps you should try some spelling variations:
nhung cong » thong cong, hang cong, nhung don
doi chieu » doc hieu, doi chi, mot chieu
hanh tran » hanh trang, thanh tran, hanh tram
dung cong » dung trong
ho chieu » theo chieu, hoc thieu, mot chieu
tran van » luan van
tac tren » rac tren, tai tren, tap tren
tren tap » tren tau, tuyen tap, tieng tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((doi chieu) OR (ho chieu)) tinh - hanh tran van ((nhung cong) or (dung cong)) tac tren tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doi chieu) OR (ho chieu)) tinh - hanh tran van ((nhung cong) OR (dung cong)) tac tren tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doi chieu) OR (ho chieu)) tinh - hanh tran van ((nhung cong) or (dung cong)) tac tren tap".
• Adding a wildcard symbol may retrieve word variants: ((doi chieu) OR (ho chieu)) tinh - hanh tran van ((nhung cong) or (dung cong)) tac tren tap*.