Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
sach ky » sac ky, sach y, sach ty
hanh di » hanh vi, hanh de, hang di
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va
nang ma » tang ma, sang ma, nang cao
ma hoi » mai hoi, xa hoi, ma hoa
sai ky » sac ky
di cua » dai cua, doi cua, de cua

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 (sai ky)) nang ma hoi. ((hieu ve) OR (hieu van)) nam thuc va hanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sai ky)) nang ma hoi. ((hieu ve) OR (hieu van)) nam thuc va hanh di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) or (sai ky)) nang ma hoi. ((hieu ve) OR (hieu van)) nam thuc va hanh di cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sai ky)) nang ma hoi. ((hieu ve) OR (hieu van)) nam thuc va hanh di cua tre*.