Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
van thanh » ban thanh, van tuan
nang dau » hang dau, xang dau, nang du
cham duc » pham duc, cham soc, pham duy
vu cham » va cham, vu kham, tu cham
tai cua » thai cua, tai cuc, tri cua
duc van » duc va, duc tan, duc manh
cua tre » cua te, cuu tre, cua triet
hieu vu » hieu va, hieu ve, hieu su
dau hoi » cau hoi, dai hoi, dan hoi
sach ty » sach y, sach tu, sach thu
sac ky » cac ky, sai ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sac ky) or (sach ty)) nang dau hoi. hieu vu cham duc van thanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sac ky) OR (sach ty)) nang dau hoi. hieu vu cham duc van thanh tai cua tre.
• Adding a wildcard symbol may retrieve word variants: su ((sac ky) or (sach ty)) nang dau hoi. hieu vu cham duc van thanh tai cua tre*.