Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
cau treo » cau theo, cau tren, cau triet
doc sach » hoc sach, nuoc sach, dac sac
va nang » van nang, da nang, cam nang
hieu va » lieu va, hieu qua
va lang » hoa lang
lang de » vang de, dang de, lang du
v nang » vu nang, van nang, voi nang
co luc » coc luc, co luy
luc va » duc va, tuc va, loc va
de cau » ke cau, le cau, ve cau
va co » vo co

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: ((toc sach) OR (doc sach)) ((v nang) OR (va nang)) xa hoi. hieu va co luc va lang de cau treo~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (doc sach)) ((v nang) OR (va nang)) xa hoi. hieu va co luc va lang de cau treo~".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) ((v nang) OR (va nang)) xa hoi. hieu va co luc va lang de cau treo*.