Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
dang xay » dang van, van xay
nam thuc » nam thuoc, am thuc, nam thu
cuu tre » cau tren, cau treo
dan vai » dan va, dan tai, dan vat
thuc ca » thuc cua, thuc can, thuc cao
qua nam » quan nam, cua nam, quang nam
sach ky » sac ky, sach y, sach ty
lang xa » lang ha, lang van
cua tre » cua te, cua triet, dua tren
ca dan » cac dan, ca dao

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

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ky ((lang xa) OR (dang xay)) hoi. hieu qua nam thuc ca dan vai ((cuu tre) OR (cua tre))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ky ((lang xa) or (dang xay)) hoi. hieu qua nam thuc ca dan vai ((cuu tre) OR (cua tre))~".
• Adding a wildcard symbol may retrieve word variants: hoc sach ky ((lang xa) or (dang xay)) hoi. hieu qua nam thuc ca dan vai ((cuu tre) OR (cua tre))*.