Perhaps you should try some spelling variations:
khoa thuoc » khong thuoc, khoa hoc, hoc thuoc
nha thuoc » nha nuoc, nhan thuc, nha hoc
nhung bo » nhung bi, nhung bai, nhung don
tu sach » thu sach, su sach, te sach
so sach » so sanh, bo sach, co sach
nhi cua » nghi cua, chi cua, khi cua
bo quoc » bo duoc, bo uoc, ho quoc
quoc li » duoc li, quoc lo, quoc gia

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