Perhaps you should try some spelling variations:
thanh trung » thanh tung
trung tuan » trung thanh, trung tam, tran tuan
tang sach » mang sach, nang sach, tvqg sach
sang sach » mang sach, ban sach, sang tac
tuan dung » tuan duong, tran dung, tan dung
dung cong » dung trong
cong tac » cong ty
toan cau » toan cao, toan tap, toan tai
toan ban » van ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((tang sach) or (sang sach)) - thanh trung tuan dung cong tac ((toan cau) OR (toan ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((tang sach) OR (sang sach)) - thanh trung tuan dung cong tac ((toan cau) OR (toan ban)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((tang sach) or (sang sach)) - thanh trung tuan dung cong tac ((toan cau) OR (toan ban))".
• Adding a wildcard symbol may retrieve word variants: hoc ((tang sach) or (sang sach)) - thanh trung tuan dung cong tac ((toan cau) OR (toan ban))*.