Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nang xa » nang x, lang xa, nang ma
hieu va » hieu qua
va danh » va dinh, va dan, va hanh
doi cua » dai cua, hoi cua
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang
xuc va » duc va, tuc va, luc va
di cua » dai cua, de cua, do cua

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 v nang xa hoi. ((hieu va) OR (lieu va)) cam xuc va danh ((di cua) OR (doi cua)) triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach v nang xa hoi. ((hieu va) or (lieu va)) cam xuc va danh ((di cua) OR (doi cua)) triet~".
• Adding a wildcard symbol may retrieve word variants: toc sach v nang xa hoi. ((hieu va) or (lieu va)) cam xuc va danh ((di cua) OR (doi cua)) triet*.