Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van ban
sach thu » sach thue, sach thieu, sach tham
van anh » van thanh, tuan anh, van minh
sach ty » sach y, sach tu, xach tay
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
ve cau » ke cau, va cau, ve cac
nang o » nang co, nang ho, nang ro
le cua » ly 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 ve cau truc ((van hanh) or (van anh)) le cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ty) OR (sach thu)) nang o hoi. hieu ve cau truc ((van hanh) OR (van anh)) le cua tre.
• Adding a wildcard symbol may retrieve word variants: te ((sach ty) or (sach thu)) nang o hoi. hieu ve cau truc ((van hanh) or (van anh)) le cua tre*.