Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
day nhanh » day thanh, duy nhanh, dac nhan
day hanh » day thanh, dao hanh, day manh
hieu van » thien van, lieu va, hieu ve
doi cua » dai cua, hoi cua
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
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 va) or (hieu van)) cham thuc ((day hanh) or (day nhanh)) doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky nang x hoi. ((hieu va) OR (hieu van)) cham thuc ((day hanh) OR (day nhanh)) doi cua tre.
• Adding a wildcard symbol may retrieve word variants: vu sach ky nang x hoi. ((hieu va) or (hieu van)) cham thuc ((day hanh) or (day nhanh)) doi cua tre*.