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

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 day ((cua tre) OR (cua te))~.
• 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 day ((cua tre) OR (cua te))~".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ky nang ma hoi. hieu vu pham thuc va doan day ((cua tre) OR (cua te))*.