Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dung tri » dung tai, dung tren, dung sai
cac cang » cac cong, cac dang, cac bang
cang thi » dang thi, can thi, tang thi
han tri » han tai, thanh tri, chan troi
van tri » van tai, van thi, van toi
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: (((( toc sach ((han tri) OR (van tri)) ) or ( te sach dung tri ))) or ( te cac cang thi ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((( toc sach ((han tri) OR (van tri)) ) OR ( te sach dung tri ))) OR ( te cac cang thi )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((( toc sach ((han tri) OR (van tri)) ) or ( te sach dung tri ))) or ( te cac cang thi ))".
• Adding a wildcard symbol may retrieve word variants: (((( toc sach ((han tri) OR (van tri)) ) or ( te sach dung tri ))) or ( te cac cang thi ))*.