Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
cau tren » cu tren, dau tren, ca tren
hieu va » lieu va, hieu qua
danh vi » hanh vi, dinh vi, danh va
danh di » danh du, xanh di, danh dien
v nang » va nang, vu nang, van nang
y nang » ky nang, ly nang, may nang
xuc va » duc va, tuc va, luc va
va cam » va cham, va cac, va cao

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: doc sach ((y nang) OR (v nang)) ma hoa. hieu va cam xuc va ((danh vi) OR (danh di)) cau tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ((y nang) or (v nang)) ma hoa. hieu va cam xuc va ((danh vi) OR (danh di)) cau tren~".
• Adding a wildcard symbol may retrieve word variants: doc sach ((y nang) or (v nang)) ma hoa. hieu va cam xuc va ((danh vi) OR (danh di)) cau tren*.