Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
vat hanh » vat thanh, van hanh, va hanh
sach ky » sac ky, sach ty, sach kem
hieu ve » hieu van
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach ky) or (sach y)) nang x hoi. ((hieu ve) or (hieu va)) nam thuc vat hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sach y)) nang x hoi. ((hieu ve) OR (hieu va)) nam thuc vat hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sach y)) nang x hoi. ((hieu ve) or (hieu va)) nam thuc vat hanh vi cua tre*.