Perhaps you should try some spelling variations:
nang van » dang van, tang van, lang van
cac thuc » cach thuc, cac thu, can thuc
cay thuc » cay thuoc, can thuc, day thuc
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
van hoc » van hoa
hieu ve » hieu va, hieu van
va xanh » va danh, va hanh, va anh
xanh di » danh di, vanh dai, xanh tai
cua tre » cua te, cuu tre, cua triet
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: tu sach ky nang van hoc. hieu ve ((cac thuc) or (cay thuc)) va xanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang van hoc. hieu ve ((cac thuc) OR (cay thuc)) va xanh di cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang van hoc. hieu ve ((cac thuc) or (cay thuc)) va xanh di cua tre*.