Perhaps you should try some spelling variations:
khan thong » khap thong, khau thong, nhan thong
thuc cach » thuoc sach, truoc cach, thuc hanh
thuong va » truong va, thong va, thuong mai
xach tay » canh tay
tay thuc » tay thu, cay thuc, day thuc
cach kho » bach khoa, cach thoi, cach pha
kho khan » khoa kham, khoa than
te xach » te sach
tu sach » thu sach, su sach, te sach
sach va » sach xa, sach ha, sach dao
va khoa » vat khoa, van khoa, da khoa
khoa he » hoa he, khoa hoc, khong he

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( te xach tay thuc cach kho khan thong ) or ( tu sach va thuong va khoa he thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te xach tay thuc cach kho khan thong ) OR ( tu sach va thuong va khoa he thong )).
• Adding a wildcard symbol may retrieve word variants: (( te xach tay thuc cach kho khan thong ) or ( tu sach va thuong va khoa he thong ))*.