Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
day thanh » dao thanh, dat thanh, da thanh
day hanh » day nhanh, dao hanh, day manh
sach ky » sac ky, sach y, sach ty
vu sach » vu bach, su sach, vu khach
hieu va » lieu va, hieu qua
hieu ve » hieu van
cua tre » cua te, cuu tre, cua triet
de cua » le cua, te cua, dieu cua
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: vu sach ky nang x hoi. ((hieu ve) OR (hieu va)) pham thuc ((day hanh) or (day thanh)) de cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky nang x hoi. ((hieu ve) OR (hieu va)) pham thuc ((day hanh) OR (day thanh)) de cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky nang x hoi. ((hieu ve) OR (hieu va)) pham thuc ((day hanh) or (day thanh)) de cua tre".
• Adding a wildcard symbol may retrieve word variants: vu sach ky nang x hoi. ((hieu ve) OR (hieu va)) pham thuc ((day hanh) or (day thanh)) de cua tre*.