Perhaps you should try some spelling variations:
tang thanh » dang thanh, trung thanh, hoang thanh
thanh toan » thanh hoa, thanh san, tinh toan
thai tang » thai trang, thai bang, thai hang
cach hoc » cach thuc, cach thoi, cac hop
dich hoc » sinh hoc, hinh hoc, tinh hoc
cuu cong » cua cong, thu cong, cac cong
cong hoc » dong hoc, cong hoa, cong coc
hoc hang » hoc hanh, hoc bang, hoc tang
hang hoa » hang khoa, thanh hoa, hang va
da thai » dao thai, do thai, ca thai
hoc da » hoc dan, hoc dai, hoc dat

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((cach hoc) or (dich hoc)) tap, nghien cuu cong hoc hang hoa hoc da thai tang thanh toan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((cach hoc) OR (dich hoc)) tap, nghien cuu cong hoc hang hoa hoc da thai tang thanh toan*.