Perhaps you should try some spelling variations:
day nhanh » day thanh, duy nhanh, dac nhan
cam thuc » am thuc, nam thuc, cam thu
day hanh » day thanh, dao hanh, day manh
hieu van » hieu va, thien van, lieu va
sach ky » sac ky, sach y, sach ty
vu sach » vu bach, su sach, vu khach
hieu ve » hieu va
nang xa » nang x, lang xa, nang ma
di cua » dai cua, doi cua, de cua
cua te » cua tu

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 xa hoi. ((hieu ve) OR (hieu van)) cam thuc ((day hanh) or (day nhanh)) di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky nang xa hoi. ((hieu ve) OR (hieu van)) cam thuc ((day hanh) OR (day nhanh)) di cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky nang xa hoi. ((hieu ve) OR (hieu van)) cam thuc ((day hanh) or (day nhanh)) di cua te".
• Adding a wildcard symbol may retrieve word variants: vu sach ky nang xa hoi. ((hieu ve) OR (hieu van)) cam thuc ((day hanh) or (day nhanh)) di cua te*.