Perhaps you should try some spelling variations:
doanh van » doan van, doanh va, doanh ban
sach tham » sach nha
sach thu » sach thue, sach thieu, cach thuc
van cua » vang cua, ban cua, dan cua
su cham » su pham, tu cham, vu cham
hieu su » hieu sau, tieu su, hieu so
bang xa » lang xa, bang va, mang xa
cua tre » cua te, cuu tre, cua triet
luc va » duc va, loc va
tuc va » thuc va, truc va, tuc xa

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 thu) OR (sach tham)) bang xa hoi. hieu su cham ((luc va) or (tuc va)) doanh van cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach thu) OR (sach tham)) bang xa hoi. hieu su cham ((luc va) OR (tuc va)) doanh van cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach thu) OR (sach tham)) bang xa hoi. hieu su cham ((luc va) or (tuc va)) doanh van cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach thu) OR (sach tham)) bang xa hoi. hieu su cham ((luc va) or (tuc va)) doanh van cua tre*.