Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
hoc sach » hoc sinh, hoc cac, hoc anh
danh di » danh du, xanh di, danh dien
hieu va » lieu va, hieu qua
ca tren » cau tren, cu tren, la tren
nang xa » nang x, lang xa, nang ma
vu nang » vuc nang, va nang, vu dang
luc va » duc va, loc va
tuc va » thuc va, truc va, tuc xa
va dao » ca dao
di ca » di cau, di cua, doi ca

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 (hoc sach)) vu nang xa hoi. hieu va dao ((luc va) OR (tuc va)) danh di ca tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (hoc sach)) vu nang xa hoi. hieu va dao ((luc va) OR (tuc va)) danh di ca tren~".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (hoc sach)) vu nang xa hoi. hieu va dao ((luc va) OR (tuc va)) danh di ca tren*.