Perhaps you should try some spelling variations:
thu doanh » thu oanh, tri doanh, thu hoach
nghiep su » nghiep sua, nghiep vu, nghiep so
va nghiep » va nghien, lam nghiep, cac nghiep
sach hay » sach han, sach ha, sach nay
doanh va » doan va, doanh tai, doanh cua
sach dat » sach dao, sach danh, sach bai
sach day » sach dao, sach dau, sach nay
nghe d » nghe di, nghe _, nghe 新
su hoc » tu hoc, du hoc, so hoc
d hoc » du hoc, ad hoc, de 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 ((((sach day) OR (sach hay))) or (sach dat)) nghe d hoc ) or ( thu doanh va nghiep su hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu ((((sach day) OR (sach hay))) OR (sach dat)) nghe d hoc ) OR ( thu doanh va nghiep su hoc ))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu ((((sach day) OR (sach hay))) or (sach dat)) nghe d hoc ) or ( thu doanh va nghiep su hoc ))*".