Perhaps you should try some spelling variations:
doanh khoa » toan khoa
thanh toan » thanh hoa, thanh san, tinh toan
som doanh » sam doanh, so doanh, hoa doanh
van thanh » ban thanh, van tuan
hoc sach » hoc sinh, hoc cac, hoc anh
sach hoc » cach hoc, sach hoi, mach hoc
khoa hoc » hoa hoc
van som » van son, van soa, nang som
xa thai » ca thai, a thai, xa hai
da thai » dao thai, do thai, ca thai

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach hoc tap, nghien cuu van som doanh khoa hoc ((xa thai) or (da thai)) van thanh toan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach hoc tap, nghien cuu van som doanh khoa hoc ((xa thai) OR (da thai)) van thanh toan.
• Adding a wildcard symbol may retrieve word variants: hoc sach hoc tap, nghien cuu van som doanh khoa hoc ((xa thai) or (da thai)) van thanh toan*.