Perhaps you should try some spelling variations:
nhung dong » nhung don, nhung cong, nhung dung
sach khoa » bach khoa, sach nha, anh khoa
thu sach » tu sach, thuat sach, thuoc sach
khoa hoc » hoa hoc
hien cao » hien cac, hien cau, khien cho
vien cao » vien cac, vien dai, vien da
co van » cao van, vo van, so van

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach khoa hoc ((hien cao) OR (vien cao)) cua ets : nhung dong co van đai~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach khoa hoc ((hien cao) OR (vien cao)) cua ets : nhung dong co van đai".
• Adding a wildcard symbol may retrieve word variants: thu sach khoa hoc ((hien cao) OR (vien cao)) cua ets : nhung dong co van đai*.