Perhaps you should try some spelling variations:
duong thanh » muong thanh, luong thanh, dung thanh
theo chieu » theo tieu, ho chieu, theo chu
chieu sach » chinh sach, chiet tach, chieu sang
dong thanh » truong thanh
mang quan » tang quan, hang quan, manh quan
nang quan » ban quan, nang suat

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

• Performing a fuzzy search may retrieve terms with similar spellings: theo chieu sach - hanh ((mang quan) or (nang quan)) nhung ((duong thanh) OR (dong thanh)) van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo chieu sach - hanh ((mang quan) OR (nang quan)) nhung ((duong thanh) OR (dong thanh)) van ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo chieu sach - hanh ((mang quan) or (nang quan)) nhung ((duong thanh) OR (dong thanh)) van ban".
• Adding a wildcard symbol may retrieve word variants: theo chieu sach - hanh ((mang quan) or (nang quan)) nhung ((duong thanh) OR (dong thanh)) van ban*.