Perhaps you should try some spelling variations:
cach thoi » cac thoi, cach thuc, cach noi
doc hieu » toc thieu, hoc thieu, hoc hien
hieu khi » hieu chi, thieu nhi, khien khi
nhung bi » nhung gi
sach ha » sach nha, sach han, sach xa
khi cua » chi cua, thai cua
ho vi » hoc vi, hoa vi, ho voi

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc ((sach ha) or (cach thoi)) doc hieu khi cua ets : ((nhung bi) OR (nhung bai)) ho vi đai~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((sach ha) OR (cach thoi)) doc hieu khi cua ets : ((nhung bi) OR (nhung bai)) ho vi đai.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((sach ha) or (cach thoi)) doc hieu khi cua ets : ((nhung bi) OR (nhung bai)) ho vi đai".
• Adding a wildcard symbol may retrieve word variants: doc ((sach ha) or (cach thoi)) doc hieu khi cua ets : ((nhung bi) OR (nhung bai)) ho vi đai*.