Perhaps you should try some spelling variations:
cach khoan » cac khoan, cach hoan, bach khoa
khan thong » khap thong, khau thong, nhan thong
sach tham » sach nha
tham thuc » nham thuc, pham thuc, tam thuc
thuc cach » thuoc sach, truoc cach, thuc hanh
khoan hoi » khoan nhoi, khoa hoi, khoa hoc
hoi tuong » hoi thuong, doi tuong, hoi luong
thuc bach » truc bach, thuoc sach, thuc hanh
sach tai » sach bai, sach dao, sach xa
tai thuc » thai thuc, tri thuc, dai thuc
bach kho » bach khoa, bac ho, benh kho
kho khan » khoa kham, khoa than
vu sach » vu bach, su sach, vu khach
tu sach » thu sach, su sach, te sach

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( vu sach tham thuc cach khoan hoi tuong ) or ( tu sach tai thuc bach kho khan thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( vu sach tham thuc cach khoan hoi tuong ) OR ( tu sach tai thuc bach kho khan thong )).
• Adding a wildcard symbol may retrieve word variants: (( vu sach tham thuc cach khoan hoi tuong ) or ( tu sach tai thuc bach kho khan thong ))*.