Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nam thuc » nam thuoc, am thuc, nam tu
cau treo » cau theo, cau tren, cau triet
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
ky lang » ky nang, ky dang, ky tang
sach ky » sac ky, sach y, sach ty
dao vai » dao va, dao bai, dao hai
dao van » do van, dang van

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ky lang xa hoi. hieu va ((nam thuc) or (nam thu)) va ((dao vai) OR (dao van)) cau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky lang xa hoi. hieu va ((nam thuc) OR (nam thu)) va ((dao vai) OR (dao van)) cau treo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky lang xa hoi. hieu va ((nam thuc) or (nam thu)) va ((dao vai) OR (dao van)) cau treo".
• Adding a wildcard symbol may retrieve word variants: toc sach ky lang xa hoi. hieu va ((nam thuc) or (nam thu)) va ((dao vai) OR (dao van)) cau treo*.