Perhaps you should try some spelling variations:
trung tuan » trung thanh, trung tam, truong thanh
nhung cong » dung cong, thong cong, hang cong
tran tuan » tran xuan, tran quang, tran thanh
hoa sinh » cho sinh
cong san » cong tac
toan cau » toan cao, toan tap, toan tai
toan ban » van ban
hoc hoa » hoc khoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hoa sinh - hanh ((trung tuan) or (tran tuan)) nhung cong san ((toan cau) or (toan ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hoa sinh - hanh ((trung tuan) OR (tran tuan)) nhung cong san ((toan cau) OR (toan ban)).
• Adding a wildcard symbol may retrieve word variants: hoc hoa sinh - hanh ((trung tuan) or (tran tuan)) nhung cong san ((toan cau) or (toan ban))*.