Perhaps you should try some spelling variations:
thanh di » thanh doi, thanh de, thanh do
toc sach » hoc sach, doc sach, thuoc sach
thi hong » thi phuong, thi hanh, thi nang
va thanh » gia thanh, ban thanh, va tinh
thi cong » tai cong, thien cong
hieu van » hieu va, thien van, lieu va
cac luc » cau luc, coc luc, cac nuoc
van cac » van hac, van cau, van bac
cua tre » cua te, cuu tre, cua triet
luc va » duc va, tuc va, loc va
di cua » dai cua, doi cua, de cua
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) ((thi hong) OR (thi cong)) x hoi. hieu van cac luc va thanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ((thi hong) OR (thi cong)) x hoi. hieu van cac luc va thanh di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) ((thi hong) OR (thi cong)) x hoi. hieu van cac luc va thanh di cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ((thi hong) OR (thi cong)) x hoi. hieu van cac luc va thanh di cua tre*.