Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
khoa thuoc » khong thuoc, khoa hoc, nha thuoc
thieu chi » thieu nhi, hieu chi, tieu chi
khoa toc » khoa hoc, hoa toc, khoa quoc
nhung bo » nhung bi, nhung bai, nhung don
chi cua » chi cuc, khi cua, cuoi cua
duoc vi » duoc li, duoc va, 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: thuoc sach ((khoa toc) or (khoa thuoc)) thieu chi cua ets : nhung bo ((duoc vi) OR (duoc si)) đai~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ((khoa toc) OR (khoa thuoc)) thieu chi cua ets : nhung bo ((duoc vi) OR (duoc si)) đai.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ((khoa toc) or (khoa thuoc)) thieu chi cua ets : nhung bo ((duoc vi) OR (duoc si)) đai".
• Adding a wildcard symbol may retrieve word variants: thuoc sach ((khoa toc) or (khoa thuoc)) thieu chi cua ets : nhung bo ((duoc vi) OR (duoc si)) đai*.