Perhaps you should try some spelling variations:
cac thuc » cach thuc, cac thu, can thuc
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, mang may
hieu ve » hieu va, hieu van
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
ve cac » va cac, vien cac
vi cua » vai cua, di cua

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 ky ((nang ma) or (nang cao)) hoa. hieu ve cac thuc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang ma) OR (nang cao)) hoa. hieu ve cac thuc va hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang ma) or (nang cao)) hoa. hieu ve cac thuc va hanh vi cua tre*.