Perhaps you should try some spelling variations:
vat hanh » vat thanh, van hanh, va hanh
cam thuc » am thuc, nam thuc, cam thu
tu sach » thu sach, te sach, tu cach
hanh de » hanh ve, hanh kem
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
ky tang » ky dang, kho tang, ky trong
su sach » so sach, vu sach
ve cam » ve cham, ve cac, va cam
de cua » le cua, te cua, dieu cua
ma noi » ha noi, ma moi, va noi

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) or (su sach)) ((ky tang) OR (ky nang)) ma noi. hieu ve cam thuc vat hanh de cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ((ky tang) OR (ky nang)) ma noi. hieu ve cam thuc vat hanh de cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) ((ky tang) OR (ky nang)) ma noi. hieu ve cam thuc vat hanh de cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ((ky tang) OR (ky nang)) ma noi. hieu ve cam thuc vat hanh de cua tre*.