Perhaps you should try some spelling variations:
khoan phai » khong phai, khoa phau, khoan hoi
thuoc dang » thuoc dung, thuoc khang, thuc dan
phai thong » phap thong, phai tuong, phan thong
tri thuoc » tri thuc, tri hoc, tin thuoc
dang khoa » dung khoa, hang khoa, dang khoi
tai thuoc » bai thuoc, tac thuoc, tao thuoc
thuoc ban » thuoc tan, thu ban, thuoc ma
ban khoan » toan khoan, cac khoan, san khoa
sach tri » sach tren, sach truc, sach bai
sach tai » sach bai, sach tham, sach dao
tu sach » thu sach, su sach, te sach
khoa he » hoa he, khoa hoc, khong he

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu sach tri thuoc dang khoa he thong ) or ( tu sach tai thuoc ban khoan phai thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach tri thuoc dang khoa he thong ) OR ( tu sach tai thuoc ban khoan phai thong )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach tri thuoc dang khoa he thong ) or ( tu sach tai thuoc ban khoan phai thong ))*.