Perhaps you should try some spelling variations:
khoan khau » khoanh khac, khoa kham, khoa phau
doanh khoa » toan khoa
khau thong » khau thuong, khap thong, khau tong
sach tren » sach tien, sach tranh
pho thong » he thong
tren thuc » trien thuc, tron thuc, trinh thuc
tu doanh » su doanh, te doanh, ty doanh
khoa pho » khoa phu, khoa khoa, khoa phau
thuc cac » thuc cach, tuc cac, phuc cac
su sach » so sach, vu sach
tren tu » tren tau, tran tu, tre tu
tu sach » thu sach, te sach, tu cach

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( su sach tren tu doanh khoa pho thong ) or ( tu sach tren thuc cac khoan khau thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( su sach tren tu doanh khoa pho thong ) OR ( tu sach tren thuc cac khoan khau thong )).
• Adding a wildcard symbol may retrieve word variants: (( su sach tren tu doanh khoa pho thong ) or ( tu sach tren thuc cac khoan khau thong ))*.