Perhaps you should try some spelling variations:
trung tuan » trung thanh, tran tuan, truong thanh
tang sach » mang sach, sang sach, tvqg sach
nang sach » mang sach, sang sach, ngan sach
dung cong » dung trong
cong tac » cong ty
tac toan » tap toan, tam toan, hach toan
toan cau » toan cao, toan ban, toan tap

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