Perhaps you should try some spelling variations:
doanh tien » doanh tren, doanh vien, doanh chien
cac doanh » cac dan, cac dang, van doanh
kinh dien » tinh dien, trinh dien
dan tren » dat tren, van tren, ran tren
dau tren » dau tien, dat tren, dau tieng
so sach » so sanh, bo sach, co sach
te cac » tu cac, ve cac, te cao

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 ((dan tren) OR (dau tren)) ) or ( so sach kinh dien ))) or ( te cac doanh tien ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((( so sach ((dan tren) OR (dau tren)) ) OR ( so sach kinh dien ))) OR ( te cac doanh tien )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((( so sach ((dan tren) OR (dau tren)) ) or ( so sach kinh dien ))) or ( te cac doanh tien ))".
• Adding a wildcard symbol may retrieve word variants: (((( so sach ((dan tren) OR (dau tren)) ) or ( so sach kinh dien ))) or ( te cac doanh tien ))*.