Perhaps you should try some spelling variations:
dau tren » dau tien, dat tren, dau tieng
tham xuc » tham nuoc, tham thuc, pham duc
hanh tai » thanh tai, hang tai, han tai
hanh vai » hanh vi, hanh va, hanh van
hieu van » thien van, lieu va, hieu ve
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
hieu va » lieu va, hieu qua
ty nang » ky nang, ty xang, ty hang
xuc va » duc va, tuc va, luc va
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: tu sach ty nang o hoi. ((hieu van) OR (hieu va)) tham xuc va ((hanh vai) OR (hanh tai)) dau tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang o hoi. ((hieu van) OR (hieu va)) tham xuc va ((hanh vai) or (hanh tai)) dau tren~".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang o hoi. ((hieu van) OR (hieu va)) tham xuc va ((hanh vai) or (hanh tai)) dau tren*.