Perhaps you should try some spelling variations:
nghiem duoc » nghiem thuoc, nghe duoc
xa nghiem » xet nghiem, van nghiem, va nghien
sac thai » rac thai, sach tham, toc thai
duoc hoc » quoc hoi
nghe va » nghe dan
tu sach » thu sach, su sach, te sach
sach xa » sach dao, sach nha, sach bai
tu sac » tu cac, tu san, tu bac
va hoc » van hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu sac thai nghe va hoc ) or ( tu sach xa nghiem duoc hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sac thai nghe va hoc ) OR ( tu sach xa nghiem duoc hoc )).
• Adding a wildcard symbol may retrieve word variants: (( tu sac thai nghe va hoc ) or ( tu sach xa nghiem duoc hoc ))*.