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