Perhaps you should try some spelling variations:
hach doanh » hanh doanh, thach hoanh, hach toan
sach trac » sach truc, sach tranh, sach tham
nghiem du » nghiem dau, nghiem de, nghiem do
nghiem d » nghiem de, nghiem do, nghiem _
thu hach » thu hoach, thu sach, tu hach
nghiep y » nghiep ly, nghiep o, nghiep cay
te sach » toc sach

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach trac ((nghiem du) OR (nghiem d)) hoc ) OR ( thu hach doanh nghiep y hoc ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( te sach trac ((nghiem du) OR (nghiem d)) hoc ) or ( thu hach doanh nghiep y hoc ))~".
• Adding a wildcard symbol may retrieve word variants: (( te sach trac ((nghiem du) OR (nghiem d)) hoc ) or ( thu hach doanh nghiep y hoc ))*.