Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van chat » cao chat
chat duc » chat xuc, chat doc, chet duoc
van hanh » van thanh, van anh, van ban
ban hanh » ban hang
sach ty » sach tu, sach thu, xach tay
cua tre » cua te, cuu tre, cua triet
ca cua » co cua

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 y) or (sach ty)) nang x ho. hieu van chat duc ((van hanh) OR (ban hanh)) ca cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach y) OR (sach ty)) nang x ho. hieu van chat duc ((van hanh) OR (ban hanh)) ca cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach y) or (sach ty)) nang x ho. hieu van chat duc ((van hanh) OR (ban hanh)) ca cua tre*".