Perhaps you should try some spelling variations:
thanh sinh » thanh binh, thanh tinh, thanh vinh
sinh cua » manh cua, dinh cuu, sinh va
tu sach » thu sach, su sach, te sach
luan va » luan van, luat va
quan va » quan vi, quan ha, quan ve
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
va sam » va am, va cam, va dam
nang o » nang co, nang ho, nang ro
va san » va ban
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: tu sach y nang o hoi. lieu ((va sam) or (va san)) ((quan va) OR (luan va)) thanh sinh cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang o hoi. lieu ((va sam) OR (va san)) ((quan va) OR (luan va)) thanh sinh cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang o hoi. lieu ((va sam) or (va san)) ((quan va) OR (luan va)) thanh sinh cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang o hoi. lieu ((va sam) or (va san)) ((quan va) OR (luan va)) thanh sinh cua tre*.