Perhaps you should try some spelling variations:
nam thuc » nam thuoc, nam thu, nam tu
cau tren » cu tren, dau tren, ca tren
sach ky » sac ky, sach ty, sach kem
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
dan tai » van tai, dan thi, han tai
tai cau » tai cac, tai cao
ca dan » cac dan, ca dao

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((sach ky) or (sach y)) lang xa hoi. hieu va ((nam thuc) or (am thuc)) ca dan tai cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((sach ky) OR (sach y)) lang xa hoi. hieu va ((nam thuc) OR (am thuc)) ca dan tai cau tren.
• Adding a wildcard symbol may retrieve word variants: hoc ((sach ky) or (sach y)) lang xa hoi. hieu va ((nam thuc) or (am thuc)) ca dan tai cau tren*.