Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
cau theo » cau thi, cau tao
hanh vai » hanh vi, hanh va, hanh tai
vat hanh » vat thanh, van hanh, va hanh
vai cau » va cau, van cau, vai cac
hieu va » lieu va, hieu qua
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
tang ma » mang may, tang van
mang xa » lang xa, mang may, dang xay
hieu ve » hieu van

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 ty ((mang xa) or (tang ma)) hoi. ((hieu ve) or (hieu va)) tham thuc vat hanh vai cau theo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((mang xa) OR (tang ma)) hoi. ((hieu ve) OR (hieu va)) tham thuc vat hanh vai cau theo.
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((mang xa) or (tang ma)) hoi. ((hieu ve) or (hieu va)) tham thuc vat hanh vai cau theo*.