Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
ky lang » ky nang, ky dang, ky tang
lang ha » long ha
cua tre » cua te, cuu tre, cua triet
ha hoi » hoa hoi, ha noi, xa hoi
ve cau » ke cau, va cau, ve 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: ((te sach) or (toc sach)) ky lang ha hoi. hieu ((ve cau) or (ket cau)) thuc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky lang ha hoi. hieu ((ve cau) OR (ket cau)) thuc va hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ky lang ha hoi. hieu ((ve cau) or (ket cau)) thuc va hanh vi cua tre*.