Perhaps you should try some spelling variations:
thanh tranh » thanh thanh, thanh tran, thanh trang
tranh cua » doanh cua, manh cua
hieu van » hieu va, thien van, hieu ve
vu sach » vu bach, su sach, vu khach
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
nang o » nang co, nang ho, nang ro
xuc va » duc va, tuc va, xac va
luc va » duc va, tuc va, loc va
o hoi » co hoi, o hoc, o hai

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach y nang o hoi. ((hieu van) or (lieu va)) bac ((xuc va) OR (luc va)) thanh tranh cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach y nang o hoi. ((hieu van) OR (lieu va)) bac ((xuc va) OR (luc va)) thanh tranh cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach y nang o hoi. ((hieu van) or (lieu va)) bac ((xuc va) OR (luc va)) thanh tranh cua tre".
• Adding a wildcard symbol may retrieve word variants: vu sach y nang o hoi. ((hieu van) or (lieu va)) bac ((xuc va) OR (luc va)) thanh tranh cua tre*.