Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
hieu thai » hieu thao, hinh thai, lieu tham
nhung don » nhung van
nhung bo » nhung bi, nhung bai, trung bo
thai cua » than cua, tai cuc, tri cua
khoa toc » khoa hoc, khoa thuoc, khoa quoc
hoa toc » hoa hoc, ho toc, hoa doc
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: thuoc sach ((khoa toc) OR (hoa toc)) hieu thai cua ets : ((nhung bo) or (nhung don)) oc vi đai~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ((khoa toc) OR (hoa toc)) hieu thai cua ets : ((nhung bo) OR (nhung don)) oc vi đai.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ((khoa toc) OR (hoa toc)) hieu thai cua ets : ((nhung bo) or (nhung don)) oc vi đai".
• Adding a wildcard symbol may retrieve word variants: thuoc sach ((khoa toc) OR (hoa toc)) hieu thai cua ets : ((nhung bo) or (nhung don)) oc vi đai*.