Perhaps you should try some spelling variations:
hieu van » hieu va, thien van
hang tai » hang va, dung tai
hanh tai » thanh tai, han tai, hinh tai
vat hanh » vat thanh, van hanh, va hanh
cau thuc » cau truc, cuu thuc, can thuc
so sach » so sanh, bo sach, co sach
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
sach ly » sach y, sach lo, sach ty
hieu ve » hieu va
tai hai » thi hai, dai hai, tai ha
ly hang » ly quang

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ly hang tai hai. ((hieu ve) or (((hieu van) OR (lieu va)))) cau thuc vat hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ly hang tai hai. ((hieu ve) OR (((hieu van) OR (lieu va)))) cau thuc vat hanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ly hang tai hai. ((hieu ve) or (((hieu van) OR (lieu va)))) cau thuc vat hanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach ly hang tai hai. ((hieu ve) or (((hieu van) OR (lieu va)))) cau thuc vat hanh tai cua tre*.