Perhaps you should try some spelling variations:
thanh trong » thanh trung, tranh trong, hanh trong
doi chieu » doc hieu, doi chi, mot chieu
ho chieu » theo chieu, hoc thieu, mot chieu
cac dung » cach dung, cac duong, cac dang
tac dung » sach dung, xay dung, tin dung
cong tan » cong tac, cong san, cong thanh
tran tap » toan tap, tran tan, tran tuan

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

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