Perhaps you should try some spelling variations:
danh doi » danh di, thanh doi, dung doi
tang van » dang van, hoang van, trong van
su sach » so sach, vu sach
doi cua » dai cua, hoi cua
xa danh » va danh, dia danh, nam danh
cac toc » cac toi, cac nuoc, cac thoi
hieu va » lieu va, hieu qua
hieu ve » hieu van
sach ty » sach y, sach tu, sach thu
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
toc xa » tuc xa, toc ta, hoc xa

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 ty ((nang ma) or (tang van)) hoi. ((hieu ve) OR (hieu va)) cac toc xa danh doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((nang ma) OR (tang van)) hoi. ((hieu ve) OR (hieu va)) cac toc xa danh doi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty ((nang ma) or (tang van)) hoi. ((hieu ve) OR (hieu va)) cac toc xa danh doi cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ty ((nang ma) or (tang van)) hoi. ((hieu ve) OR (hieu va)) cac toc xa danh doi cua tre*.