Perhaps you should try some spelling variations:
hien nghe » hiem ngheo, nhiem nghe, gian nghe
khoa hoc » hoa hoc
nhung bo » nhung bi, nhung bai, nhung don
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
nha hoc » nha thuoc, nha nuoc, thai hoc
dan ets » dan ts
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: ((tu sach) or (su sach)) ((nha hoc) OR (khoa hoc)) hien nghe dan ets : nhung bo co vi đai~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ((nha hoc) OR (khoa hoc)) hien nghe dan ets : nhung bo co vi đai.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) ((nha hoc) OR (khoa hoc)) hien nghe dan ets : nhung bo co vi đai".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ((nha hoc) OR (khoa hoc)) hien nghe dan ets : nhung bo co vi đai*.