Perhaps you should try some spelling variations:
khoan phai » khong phai, khoa phau, khoan hoi
phai thong » phap thong, phai tuong, phan thong
thuoc toan » thuoc tan, thuoc thanh, thuat toan
anh khoan » anh khoa, anh nhan, anh hoang
bai thuoc » ban thuoc, bai hoc, cay thuoc
pho thong » he thong
thuc anh » thuc hanh, thuy anh, thu anh
sach bai » sach dao, cac bai, sach xa
khoa pho » khoa phu, khoa khoa, khoa phau
te sach » toc sach
sach va » sach xa, sach ha, sach dao
vu sach » vu bach, su sach, vu khach

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( te sach va thuc anh khoan phai thong ) or ( vu sach bai thuoc toan khoa pho thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach va thuc anh khoan phai thong ) OR ( vu sach bai thuoc toan khoa pho thong )).
• Adding a wildcard symbol may retrieve word variants: (( te sach va thuc anh khoan phai thong ) or ( vu sach bai thuoc toan khoa pho thong ))*.