Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
vat dinh » va dinh, van dinh, vat sinh
dinh dai » dinh dat, sinh dai, dinh dao
sach ky » sac ky, sach y, sach ty
ky dang » ky nang, ky danh
dang xa » dang xay, lang xa, dang ha
hieu ve » hieu va
cua tre » cua te, cuu tre, cua triet

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 ky dang xa hoi. ((hieu ve) OR (hieu van)) cham thuc vat dinh dai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky dang xa hoi. ((hieu ve) OR (hieu van)) cham thuc vat dinh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ky dang xa hoi. ((hieu ve) OR (hieu van)) cham thuc vat dinh dai cua tre*.