Perhaps you should try some spelling variations:
dung doi » huong doi, dung tai, dung co
danh doi » danh di, thanh doi, danh hoa
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
cac toc » cac toi, cac nuoc, cac thoi
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
toc xa » tuc xa, toc ta, hoc xa
ma hoi » xa hoi, ma hoa, me hoi
ve cac » va cac, vien cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ky nang ((ma hoi) or (mai hoi)). hieu ve cac toc xa ((danh doi) OR (dung doi)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky nang ((ma hoi) OR (mai hoi)). hieu ve cac toc xa ((danh doi) OR (dung doi)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky nang ((ma hoi) or (mai hoi)). hieu ve cac toc xa ((danh doi) OR (dung doi)) cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach ky nang ((ma hoi) or (mai hoi)). hieu ve cac toc xa ((danh doi) OR (dung doi)) cua tre*.