Perhaps you should try some spelling variations:
phap thong » phap phong, phap chong, pho thong
khoan phai » khong phai, khoa phau, khoan hoi
phai thong » phai tuong, phan thong, khai thuong
sach tren » sach tien, sach tranh
khoa phap » khoa phau, khong phap, hoa phan
tri thuoc » tri thuc, tri hoc, tin thuoc
thuoc cao » thuoc co, thuc cao, thuoc bao
cao khoan » cac khoan, tao khoang, lao khoa
tren tuc » tren thuc, trong tuc, tren thi
cao khoa » lao khoa, bao khoa, cac khoa
sach tri » sach tai, sach truc, sach bai
tu sach » thu sach, su sach, te sach
tuc cao » thuc cao, tuc co, tuc cac

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 tren tuc cao khoa phap thong ) or ( tu sach tri thuoc cao khoan phai thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach tren tuc cao khoa phap thong ) OR ( tu sach tri thuoc cao khoan phai thong )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach tren tuc cao khoa phap thong ) or ( tu sach tri thuoc cao khoan phai thong ))*.