Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
day nhanh » day thanh, duy nhanh, day manh
day hanh » day thanh, dao hanh, day manh
dac nhan » cac nhan, danh nhan, ca nhan
sach ty » sach y, sach tu, sach thu
vu sach » vu bach, su sach, vu khach
ve pham » vi pham, v pham, ve phan
hieu ve » hieu va, hieu van
ty nang » ky nang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet
nang o » nang co, nang ho, nang ro
de cua » le cua, te cua, dieu cua
o hoi » co hoi, o hoc, o hai

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 ty nang o hoi. hieu ve pham thuc ((day hanh) or (((day nhanh) or (dac nhan)))) de cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ty nang o hoi. hieu ve pham thuc ((day hanh) OR (((day nhanh) OR (dac nhan)))) de cua tre.
• Adding a wildcard symbol may retrieve word variants: vu sach ty nang o hoi. hieu ve pham thuc ((day hanh) or (((day nhanh) or (dac nhan)))) de cua tre*.