Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
sach ty » sach y, sach tu, xach tay
van cac » van hac, van cau, van bac
cua tre » cua te, cuu tre, cua triet
nang o » nang co, nang ho, nang ro
cac co » cac cong
co van » cao van, vo van, so van
vi cua » vai cua, di cua
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: te ((sach ty) OR (sach thu)) nang o hoi. hieu van cac co van hanh vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ty) OR (sach thu)) nang o hoi. hieu van cac co van hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: te ((sach ty) OR (sach thu)) nang o hoi. hieu van cac co van hanh vi cua tre*.