Perhaps you should try some spelling variations:
dung doi » huong doi, dung tai, dung co
danh doi » danh di, thanh doi, danh hoa
tang van » dang van, hoang van, trong van
su sach » so sach, vu sach
sach tu » sach thu, cach tu, sach ty
cac toc » cac toi, cac nuoc, cac thoi
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
nang ma » tang ma, sang ma, nang cao
toc xa » tuc xa, toc ta, hoc xa
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 tu ((nang ma) or (tang van)) 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: su sach tu ((nang ma) OR (tang van)) 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: "su sach tu ((nang ma) or (tang van)) hoi. hieu ve cac toc xa ((danh doi) OR (dung doi)) cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach tu ((nang ma) or (tang van)) hoi. hieu ve cac toc xa ((danh doi) OR (dung doi)) cua tre*.