Perhaps you should try some spelling variations:
gap phoi » cap phoi, gap phai, cay phoi
van dung » van dong, xay dung, tin dung
nam thuc » nam thuoc, nam thu, nam tu
cua tre » cua te, cuu tre, cua triet
dung ca » dung cua, dung cac, dung cam
hieu ve » hieu va, hieu van
ca phoi » cap phoi, cay phoi
ky dang » ky nang, ky danh
sai ky » sac ky
ca cua » co cua
so sai » so dai, so hai, do sai

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sai ky dang ((ca phoi) OR (gap phoi)). hieu ve ((nam thuc) or (am thuc)) van dung ca cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sai ky dang ((ca phoi) OR (gap phoi)). hieu ve ((nam thuc) OR (am thuc)) van dung ca cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sai ky dang ((ca phoi) OR (gap phoi)). hieu ve ((nam thuc) or (am thuc)) van dung ca cua tre*".