Perhaps you should try some spelling variations:
hien nghe » hiem ngheo, nhiem nghe, gian nghe
toc sach » hoc sach, doc sach, thuoc sach
nhung bo » nhung bi, nhung bai, nhung don
su sach » so sach, vu sach
nha hoc » nha thuoc, khoa hoc, nha nuoc
nghe va » nghe dan
bo co » bao co, vo co, co co
co vi » co vai, co va, co gi

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((((te sach) OR (toc sach))) or (su sach)) nha hoc hien nghe va ets : nhung bo co vi đai~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((((te sach) OR (toc sach))) OR (su sach)) nha hoc hien nghe va ets : nhung bo co vi đai.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((te sach) OR (toc sach))) or (su sach)) nha hoc hien nghe va ets : nhung bo co vi đai".
• Adding a wildcard symbol may retrieve word variants: ((((te sach) OR (toc sach))) or (su sach)) nha hoc hien nghe va ets : nhung bo co vi đai*.