Perhaps you should try some spelling variations:
thien van » thi van
xach tay » canh tay
nang dau » hang dau, xang dau, nang du
danh tai » doanh tai, dinh tai, hanh tai
hieu van » hieu va, lieu va, hieu ve
cam luc » cam xuc, cau luc
tai cua » thai cua, tai cuc, tri cua
va danh » va dinh, va dan, va hanh
dau hoi » cau hoi, dai hoi, dan hoi
cua tre » cua te, cuu tre, cua triet
luc va » duc va, tuc va, loc va

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach y) OR (xach tay)) nang dau hoi. ((hieu van) OR (thien van)) cam luc va danh tai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach y) or (xach tay)) nang dau hoi. ((hieu van) OR (thien van)) cam luc va danh tai cua tre~".
• Adding a wildcard symbol may retrieve word variants: su ((sach y) or (xach tay)) nang dau hoi. ((hieu van) OR (thien van)) cam luc va danh tai cua tre*.