Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
van thanh » ban thanh, van tuan
thanh dai » thanh hai, thanh tai, thanh dat
hieu van » hieu va, thien van, lieu va
sach tu » sach thu, cach tu, sach ty
tu xang » ty xang, tu lang, tu quang
van hoc » van hoa
hoc dau » hoc dan, hoc dai, hoc dat
dau van » dao van, dam van, dau va
cua tre » cuu tre, cua triet, dua tren
xang o » lang o, tang o, dang o
cua te » cua tu
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: thuat sach tu xang o hoi. hieu van hoc dau van thanh dai ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach tu xang o hoi. hieu van hoc dau van thanh dai ((cua tre) OR (cua te)).
• Adding a wildcard symbol may retrieve word variants: thuat sach tu xang o hoi. hieu van hoc dau van thanh dai ((cua tre) or (cua te))*.