Perhaps you should try some spelling variations:
khoa thuoc » khong thuoc, khoa hoc, nha thuoc
nhung don » nhung van
khoa toc » khoa hoc, hoa toc, khoa quoc
nhung bo » nhung bi, nhung bai, trung bo
tu sach » thu sach, su sach, te sach
nhi cua » nghi cua, chi cua, khi cua
oc vi » hoc vi, doc vi

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 ((khoa toc) or (khoa thuoc)) thieu nhi cua ets : ((nhung don) OR (nhung bo)) oc vi đai~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((khoa toc) OR (khoa thuoc)) thieu nhi cua ets : ((nhung don) OR (nhung bo)) oc vi đai.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((khoa toc) or (khoa thuoc)) thieu nhi cua ets : ((nhung don) OR (nhung bo)) oc vi đai".
• Adding a wildcard symbol may retrieve word variants: tu sach ((khoa toc) or (khoa thuoc)) thieu nhi cua ets : ((nhung don) OR (nhung bo)) oc vi đai*.