Perhaps you should try some spelling variations:
doanh cua » doanh luan
nang dau » hang dau, xang dau, nang du
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
cua cua » cua chua, ca cua, qua cua
ve cham » va cham, ve chat, vu cham
dau hoi » cau hoi, dai hoi, dan hoi
cua tre » cua te, cuu tre, cua triet
ve cam » ve cac, va cam, ve cai
lo va » lo van, lao va, le va

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang dau hoi. hieu ((ve cam) or (ve cham)) ((lo va) or (ly va)) doanh cua cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang dau hoi. hieu ((ve cam) OR (ve cham)) ((lo va) OR (ly va)) doanh cua cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang dau hoi. hieu ((ve cam) or (ve cham)) ((lo va) or (ly va)) doanh cua cua tre*.