Perhaps you should try some spelling variations:
dua tren » dung tren
toc sach » hoc sach, doc sach, thuoc sach
dinh tri » chinh tri
chat xuc » chat huu, chao xu, chat cua
tri dua » tri cua, thi dua, tri du
va dinh » van dinh, va kinh, va tinh
hieu va » lieu va, hieu qua
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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: ((te sach) OR (toc sach)) ky nang o hoi. hieu va ((chat xuc) OR (cam xuc)) va dinh tri dua tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) ky nang o hoi. hieu va ((chat xuc) OR (cam xuc)) va dinh tri dua tren~".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ky nang o hoi. hieu va ((chat xuc) OR (cam xuc)) va dinh tri dua tren*.