Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
hoc sach » hoc sinh, hoc cac, hoc anh
sach ky » sac ky, sach y, sach ty
thi van » thi lan, thi hanh, thi nang
thuc ca » thuc cua, thuc can, thuc cao
van dau » van dao, phan dau
dau cua » dai cua, day cua, cau cua
cua tre » cua te, cuu tre, cua triet
ca van » cac van, cao van, can van
x hoi » xa hoi, o hoi, x ho

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach ky nang x hoi. ((thien van) or (thi van)) tham thuc ca van dau cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ky nang x hoi. ((thien van) OR (thi van)) tham thuc ca van dau cua tre.
• Adding a wildcard symbol may retrieve word variants: hoc sach ky nang x hoi. ((thien van) or (thi van)) tham thuc ca van dau cua tre*.