Perhaps you should try some spelling variations:
nguoi sach » nguoi san, nuoc sach
sach khoan » cac khoan, bach khoa, sach han
khoan phai » khong phai, khoa phau, khoan hoi
phai thong » phap thong, phai tuong, phan thong
tri nguoi » tri nguon, tren nguoi, toc nguoi
sach tri » sach tai, sach tren, sach truc
hoc hong » hoc huong, hoc khong, hoc cong
tri ngan » tai ngan, tri nhan, thi ngan
tu sach » thu sach, su sach, te sach
nha hoc » nha thuoc, khoa hoc, nha nuoc

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 nguoi sach nha hoc hong ) or ( tu sach tri ngan sach khoan phai thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach tri nguoi sach nha hoc hong ) OR ( tu sach tri ngan sach khoan phai thong )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach tri nguoi sach nha hoc hong ) or ( tu sach tri ngan sach khoan phai thong ))*.