Perhaps you should try some spelling variations:
dang xay » dang van
va thanh » gia thanh, ban thanh, va tinh
tu sach » thu sach, su sach, te sach
cac tac » cac toc, cac bac, cac dac
doi cua » dai cua, hoi cua
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
tac va » tac da, tac xa, tuc va
di cua » dai cua, de cua, do cua
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: tu sach ky ((dang xay) OR (van xay)) hoi. hieu ve cac tac va thanh ((di cua) or (doi cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((dang xay) OR (van xay)) hoi. hieu ve cac tac va thanh ((di cua) OR (doi cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((dang xay) OR (van xay)) hoi. hieu ve cac tac va thanh ((di cua) or (doi cua)) tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((dang xay) OR (van xay)) hoi. hieu ve cac tac va thanh ((di cua) or (doi cua)) tre*.