Perhaps you should try some spelling variations:
nghiem duoc » nghiem thuoc, nghe duoc
xa nghiem » xet nghiem, van nghiem, va nghien
sach thai » sac thai, sach tai, sach nha
sach tham » sach nha
duoc hoc » quoc hoi
so sach » so sanh, bo sach, co sach
sach xa » sach dao, sach nha, sach bai
xu hoc » tu hoc, du hoc, xa hoc
su hoc » tu hoc, du hoc, so hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( so sach xa nghiem duoc hoc ) or ( su ((sach thai) OR (sach tham)) nghe ((xu hoc) or (su hoc)) ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( so sach xa nghiem duoc hoc ) OR ( su ((sach thai) OR (sach tham)) nghe ((xu hoc) OR (su hoc)) )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( so sach xa nghiem duoc hoc ) or ( su ((sach thai) OR (sach tham)) nghe ((xu hoc) or (su hoc)) ))".
• Adding a wildcard symbol may retrieve word variants: (( so sach xa nghiem duoc hoc ) or ( su ((sach thai) OR (sach tham)) nghe ((xu hoc) or (su hoc)) ))*.