Perhaps you should try some spelling variations:
trung tuan » trung thanh, trung tam, truong thanh
tran tuan » tran xuan, tran quang, tran thanh
hang cong » hang nong, bang cong, thanh cong
dang cong » dung cong
thi hanh » thi thanh
toan cao » toan ban, toan tap
doi thi » doi thoi, do thi, doi khi

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi thi hanh - hanh ((trung tuan) OR (tran tuan)) ((hang cong) or (dang cong)) tinh toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi thi hanh - hanh ((trung tuan) OR (tran tuan)) ((hang cong) OR (dang cong)) tinh toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doi thi hanh - hanh ((trung tuan) OR (tran tuan)) ((hang cong) or (dang cong)) tinh toan cao".
• Adding a wildcard symbol may retrieve word variants: doi thi hanh - hanh ((trung tuan) OR (tran tuan)) ((hang cong) or (dang cong)) tinh toan cao*.