Perhaps you should try some spelling variations:
khoan phau » khoa phau, khoan phai, khoa chau
phau thong » phap thong, khau thong, phan thong
sach tren » sach tien, sach tranh
tren thuc » trien thuc, tron thuc, trinh thuc
thuc cach » thuoc sach, truoc cach, thuc hanh
phi thong » phi thuong, pho thong, phi trong
thuc cac » tuc cac, phuc cac, thac cac
sach tai » sach bai, sach tham, sach dao
tai thuc » thai thuc, tri thuc, dai thuc
cach thi » cach thoi, cac thi, cach thien
tu sach » thu sach, su sach, te sach
thi phi » chi phi, phi phi, thi phu

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 thuc cac khoan phau thong ) or ( tu sach tai thuc cach thi phi thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach tren thuc cac khoan phau thong ) OR ( tu sach tai thuc cach thi phi thong )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach tren thuc cac khoan phau thong ) or ( tu sach tai thuc cach thi phi thong ))*.