Perhaps you should try some spelling variations:
thanh thang » nhanh thang, thanh thanh, thanh hang
thang cua » thong cua, hang cua, than cua
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach ty, sach kem
ve cac » va cac, vien cac
nang o » nang co, nang ho, nang ro
o hai » co hai, so hai, o lai

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 ky) or (sach y)) nang o hai. hieu ve cac ((duc minh) OR (duc anh)) thanh thang cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ky) OR (sach y)) nang o hai. hieu ve cac ((duc minh) OR (duc anh)) thanh thang cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ky) or (sach y)) nang o hai. hieu ve cac ((duc minh) OR (duc anh)) thanh thang cua tre*".