Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
duy nhanh » duy khanh, day nhanh, duy anh
hieu van » hieu va, thien van, lieu va
van cham » van chat, van tham, va cham
day hanh » day nhanh, day thanh, dao hanh
vu sach » vu bach, su sach, vu khach
ha manh » ho manh, ha anh, ha thanh
cuu tre » cua tre, cau tren, cau treo
sach ky » sac ky, sach y, sach ty
di cuu » di cau, di cua, dinh cuu
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 van cham thuc ((((day hanh) or (ha manh))) or (duy nhanh)) di cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky nang x hoi. hieu van cham thuc ((((day hanh) OR (ha manh))) OR (duy nhanh)) di cuu tre.
• Adding a wildcard symbol may retrieve word variants: vu sach ky nang x hoi. hieu van cham thuc ((((day hanh) or (ha manh))) or (duy nhanh)) di cuu tre*.