Perhaps you should try some spelling variations:
sach khoa » bach khoa, sach nha, anh khoa
hoc thieu » toc thieu, hoc hien
thieu chi » thieu nhi, hieu chi, tieu chi
khoa hoc » hoa hoc
trung bo » truong bo, trung hoc, trung hoa
tu sach » thu sach, su sach, te sach
chi cua » chi cuc, khi cua, cuoi cua
co vi » co vai, co gi, co ki
co va » co ma, do va, so va

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