Perhaps you should try some spelling variations:
khoan phai » khong phai, khoa phau, khoan hoi
khap thong » phap thong, khau thong, khac thuong
phai thong » phap thong, phai tuong, phan thong
tham toan » pham toan, tam toan, thuat toan
khoa khap » khoa kham, khoa khac, kho khan
sach tren » sach tien, sach tranh
tren thuc » trien thuc, tron thuc, trinh thuc
toc sach » hoc sach, doc sach, thuoc sach
sach tri » sach tai, sach truc, sach bai
tri tham » thi tham, tri cham, tri tam
thuc cac » thuc cach, tuc cac, phuc cac
tu sach » thu sach, su sach, te sach

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

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