Perhaps you should try some spelling variations:
sach thi » sach thu, sach tai, sach thieu
thi nang » thi cong, ki nang, thi hanh
cac thuc » cach thuc, cac thu, can thuc
hanh hai » thanh hai, nhanh hai, hang hai
te sach » toc sach
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach thi nang ma hoi. ((hieu va) OR (hieu qua)) cac thuc va hanh hai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach thi nang ma hoi. ((hieu va) OR (hieu qua)) cac thuc va hanh hai cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach thi nang ma hoi. ((hieu va) OR (hieu qua)) cac thuc va hanh hai cua tre*.