Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
hanh vai » hanh vi, hanh va, hanh tai
xay hanh » day nhanh, day thanh, xanh hanh
hieu van » thien van, lieu va, hieu ve
thuc xay » thuc day, tuc xay, thuat xay
te sach » toc sach
ty sang » ty xang, ty hang, duy sang
vai cua » dai cua, hai cua, lai cua
sach ty » sach y, sach tu, sach thu
hieu va » lieu va, hieu qua
ma hoi » mai hoi, ma hoa, me hoi
cua te » cua tu

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 ty sang ((ma hoi) or (xa hoi)). ((hieu van) OR (hieu va)) nam thuc xay hanh vai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty sang ((ma hoi) OR (xa hoi)). ((hieu van) OR (hieu va)) nam thuc xay hanh vai cua te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty sang ((ma hoi) or (xa hoi)). ((hieu van) OR (hieu va)) nam thuc xay hanh vai cua te*".