Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, thai thuc
hieu van » hieu va, thien van, lieu va
thu sach » tu sach, thuat sach, thuoc sach
tam thuc » am thuc, nam thuc, dam thuc
va hanh » van hanh, va thanh, va danh
tu cach » tu cac
nang co » nang cao, nang doc, nang noi
cua tre » cua te, cuu tre, cua triet
co loi » co hoi
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 cach) or (thu sach)) ky nang co loi. hieu van ((tam thuc) OR (tham thuc)) va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu cach) OR (thu sach)) ky nang co loi. hieu van ((tam thuc) OR (tham thuc)) va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu cach) or (thu sach)) ky nang co loi. hieu van ((tam thuc) OR (tham thuc)) va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu cach) or (thu sach)) ky nang co loi. hieu van ((tam thuc) OR (tham thuc)) va hanh vi cua tre*.