Perhaps you should try some spelling variations:
tang thanh » dang thanh, trung thanh, hoang thanh
thanh tai » thanh hai, thanh toan, doanh tai
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
cao duc » cao suc, giao duc, tao duoc
tai cuu » tai cuc, tai buu, tai cua
dao duc » giao duc, tao duoc
cuu tre » cua tre, cau tren, cau treo
te sach » toc sach
nang o » nang co, nang ho, nang ro
y nang » ky nang, ly nang, v nang
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: ((thu sach) or (te sach)) y nang o hoi. hieu van ((cao duc) or (dao duc)) tang thanh tai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (te sach)) y nang o hoi. hieu van ((cao duc) OR (dao duc)) tang thanh tai cuu tre.
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (te sach)) y nang o hoi. hieu van ((cao duc) or (dao duc)) tang thanh tai cuu tre*.