Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
toc sach » hoc sach, doc sach, thuoc sach
dau cua » dai cua, day cua, cau cua
va doan » va doanh, van doan, va don
vu pham » su pham, vi pham, vu kham
hieu vu » hieu va, hieu ve, hieu su
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
va dan » ca dan, va dao, va dau

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky nang ma hoi. hieu vu pham thuc ((va doan) OR (va dan)) dau cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) ky nang ma hoi. hieu vu pham thuc ((va doan) or (va dan)) dau cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) ky nang ma hoi. hieu vu pham thuc ((va doan) or (va dan)) dau cua tre*.