Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
thuc day » thuc dan, thuc vat
ky dang » ky nang, ky danh
dang xa » dang xay, lang xa, dang ha
hieu ve » hieu va, hieu van
hieu su » hieu sau, tieu su, hieu so
day dau » day du, day sau, dan dau
su tien » su kien, su hien, tu tieng
te sac » te sach, te cac, te san
sac ky » cac ky, sai ky
dau vi » dau ve, dau va, dat vi
vi su » va su, ve su, ki su

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te sac ky dang xa hoi. ((hieu ve) or (hieu su)) pham thuc day dau vi su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky dang xa hoi. ((hieu ve) OR (hieu su)) pham thuc day dau vi su tien.
• Adding a wildcard symbol may retrieve word variants: te sac ky dang xa hoi. ((hieu ve) or (hieu su)) pham thuc day dau vi su tien*.