Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
cac thuc » cach thuc, cac thu, can thuc
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
hieu ve » hieu va, hieu van
ky dang » ky nang, ky danh
ky lang » ky nang, ky tang, tay lang
te sach » toc sach
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: ((thu sach) or (te sach)) ((ky lang) OR (ky dang)) ha noi. hieu ve cac thuc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (te sach)) ((ky lang) OR (ky dang)) ha noi. hieu ve cac thuc va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (te sach)) ((ky lang) OR (ky dang)) ha noi. hieu ve cac thuc va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (te sach)) ((ky lang) OR (ky dang)) ha noi. hieu ve cac thuc va hanh vi cua tre*.