Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dang xay » dang van, van xay
cac luc » cau luc, coc luc, cac nuoc
cua tre » cua te, cua triet, dua tren
hanh di » hanh vi, hanh de, hang di
va hanh » van hanh, va thanh, va danh
hieu va » lieu va
xay hoi » xa hoi, tay hoi, cay phoi
cuu tre » cau tren, cau treo
sach v » sach va, sach y, sach 2
luc va » duc va, tuc va, loc va
v dang » vu dang, va dang, 2 dang

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 v dang xay hoi. ((hieu va) OR (hieu qua)) cac luc va hanh di ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach v dang xay hoi. ((hieu va) OR (hieu qua)) cac luc va hanh di ((cua tre) OR (cuu tre))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach v dang xay hoi. ((hieu va) OR (hieu qua)) cac luc va hanh di ((cua tre) or (cuu tre))*".