Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
day thanh » dao thanh, dat thanh, da thanh
sach thi » sach thu, sach tai, sach thieu
thi nang » thi cong, ki nang, thi hanh
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, nam thu, nam tu
so sach » so sanh, bo sach, co sach
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach thi nang xa hoi. hieu van ((nam thuc) OR (am thuc)) day thanh dai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach thi nang xa hoi. hieu van ((nam thuc) OR (am thuc)) day thanh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach thi nang xa hoi. hieu van ((nam thuc) OR (am thuc)) day thanh dai cua tre*.