Perhaps you should try some spelling variations:
dang xay » dang van, van xay
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
lang xa » lang ha, lang van
hieu ve » hieu va, hieu van
va kinh » va tinh, qua kinh
kinh vi » dinh vi, kinh ve, kenh vi
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua
nuoc » quoc, duoc, ngoc

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 (lang xa)) hoi. hieu ve ((cac hop) or (dat nuoc)) va kinh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((dang xay) OR (lang xa)) hoi. hieu ve ((cac hop) OR (dat nuoc)) va kinh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((dang xay) or (lang xa)) hoi. hieu ve ((cac hop) or (dat nuoc)) va kinh vi cua tre*.