Perhaps you should try some spelling variations:
dan khanh » dang khanh, van khanh, dat khanh
cua triet » cua viet, su triet, va triet
cac thuc » cach thuc, cac thu, can thuc
dan hanh » dang hanh, dan thanh, ban hanh
so sach » so sanh, bo sach, co sach
qua cac » cua cac
v nang » va nang, vu nang, van nang
di cua » dai cua, doi cua, de cua

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 ((v nang) or (van ban)) xa hoi. hieu qua cac thuc ((dan hanh) OR (dan khanh)) di cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ((v nang) OR (van ban)) xa hoi. hieu qua cac thuc ((dan hanh) OR (dan khanh)) di cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ((v nang) or (van ban)) xa hoi. hieu qua cac thuc ((dan hanh) OR (dan khanh)) di cua triet".
• Adding a wildcard symbol may retrieve word variants: so sach ((v nang) or (van ban)) xa hoi. hieu qua cac thuc ((dan hanh) OR (dan khanh)) di cua triet*.