Perhaps you should try some spelling variations:
dang xay » van xay
dinh vai » dinh van, dinh va, dinh tai
dang van » hoang van, hang va
tu sach » thu sach, su sach, te sach
dinh vi » dinh ve, dinh viet, dinh tri
sach ty » sach y, sach tu, sach thu
hieu ve » hieu va, hieu van
cuu tre » cua tre, cau tren, cau treo
am hoc » ad hoc
ve am » va am

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ty ((dang xay) or (dang van)) hoi. hieu ve am hoc va ((dinh vai) OR (dinh vi)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((dang xay) OR (dang van)) hoi. hieu ve am hoc va ((dinh vai) OR (dinh vi)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty ((dang xay) or (dang van)) hoi. hieu ve am hoc va ((dinh vai) OR (dinh vi)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((dang xay) or (dang van)) hoi. hieu ve am hoc va ((dinh vai) OR (dinh vi)) cuu tre*.