Perhaps you should try some spelling variations:
sach hieu » sach thieu, sach tien, manh hieu
hieu thuc » hieu thuoc, hien thuc, hieu tuc
thuc hach » thuc hanh, chuc hach, thuc cach
hach toan » thanh toan, manh toan
toan phan » thanh phan, toan ban, hoa phan
phan tong » phan trong, phan cong, han tong
khoan pho » khoan nhoi, khoan phai, khoan hoi
pho thong » he thong
toc sach » hoc sach, doc sach, thuoc sach
thu sach » tu sach, thuat sach, thuoc sach
sach dai » sach dao, sach bai, sach dat
dai thuc » dan thuc, dai thu, dai thua
thuc cac » thuc cach, tuc cac, phuc cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( toc sach hieu thuc hach toan phan tong ) or ( thu sach dai thuc cac khoan pho thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( toc sach hieu thuc hach toan phan tong ) OR ( thu sach dai thuc cac khoan pho thong )).
• Adding a wildcard symbol may retrieve word variants: (( toc sach hieu thuc hach toan phan tong ) or ( thu sach dai thuc cac khoan pho thong ))*.