Perhaps you should try some spelling variations:
dung doi » huong doi, dung tai, dung co
danh doi » danh di, thanh doi, danh hoa
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
cac tuc » cac toc, cac tu, cac tac
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
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: su sach ky ((nang ma) or (tang ma)) hoi. hieu ve cac tuc xa ((danh doi) OR (dung doi)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang ma) OR (tang ma)) hoi. hieu ve cac tuc xa ((danh doi) OR (dung doi)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((nang ma) or (tang ma)) hoi. hieu ve cac tuc xa ((danh doi) OR (dung doi)) cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang ma) or (tang ma)) hoi. hieu ve cac tuc xa ((danh doi) OR (dung doi)) cua tre*.