Perhaps you should try some spelling variations:
xang dau » hang dau
sach ky » sac ky, sach y, sach kem
sach ty » sach y, sach tu, sach thu
dau hoi » cau hoi, dai hoi, dan hoi
hieu ve » hieu va, hieu van
luc van » luoc van, luu van, duc van
anh tai » hanh tai, anh thai, vanh tai
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
ve cam » ve cham, ve cac, va cam
luan » quan, lan

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)) xang dau hoi. hieu ve cam ((luc van) or (luan van)) anh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sach ty)) xang dau hoi. hieu ve cam ((luc van) OR (luan van)) anh tai cua tre.
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sach ty)) xang dau hoi. hieu ve cam ((luc van) or (luan van)) anh tai cua tre*.