Perhaps you should try some spelling variations:
phap thong » phap phong, phap chong, pho thong
sach tren » sach tien, sach tranh
tren duoc » tren duong, trong duoc, tranh duoc
kham trai » khac trai, khach trai, pham tai
trai thuc » tri thuc, thai thuc, tra thuc
thuc cach » thuoc sach, truoc cach, thuc hanh
cach khoa » bach khoa, cac khoa, cac khoan
khoa phap » khoa phau, khoan phai, khong phap
duoc cac » cuoc cach, duoc chat, duong cac
cac khoi » cac thoi, cac khoan, cach thoi
su sach » so sach, vu sach
khoi he » khoa he, khoi de, khong he
vu kham » vu khanh

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 duoc cac khoi he thong ) or ( vu kham trai thuc cach khoa phap thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( su sach tren duoc cac khoi he thong ) OR ( vu kham trai thuc cach khoa phap thong )).
• Adding a wildcard symbol may retrieve word variants: (( su sach tren duoc cac khoi he thong ) or ( vu kham trai thuc cach khoa phap thong ))*.