Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
van thanh » ban thanh, van tuan
hieu van » hieu va, thien van, lieu va
nang dau » hang dau, xang dau, nang du
tai cua » thai cua, tai cuc, tri cua
luc van » luoc van, luu van, duc van
cam luc » cam xuc, cau luc
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach kem
hieu ve » hieu va
dau hoi » cau hoi, dai hoi, dan hoi
sach ty » sach y, sach tu, sach thu

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach ky) or (sach ty)) nang dau hoi. ((hieu ve) OR (hieu van)) cam luc van thanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sach ty)) nang dau hoi. ((hieu ve) OR (hieu van)) cam luc van thanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) or (sach ty)) nang dau hoi. ((hieu ve) OR (hieu van)) cam luc van thanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sach ty)) nang dau hoi. ((hieu ve) OR (hieu van)) cam luc van thanh tai cua tre*.