Perhaps you should try some spelling variations:
cac thuc » cach thuc, cac thu, can thuc
thuc dan » thuc hanh, hoc dan, thuc vat
cua viet » ca viet, hoa viet, cua vat
so sach » so sanh, bo sach, co sach
qua cac » cua cac
hanh di » hanh vi, hanh de, danh di
hang di » hang doi, hang vi, hang dien
v nang » va nang, vu nang, van nang

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 di) OR (hang di)) cua viet~.
• 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 di) OR (hang di)) cua viet.
• 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 di) OR (hang di)) cua viet".
• Adding a wildcard symbol may retrieve word variants: so sach ((v nang) or (van ban)) xa hoi. hieu qua cac thuc dan ((hanh di) OR (hang di)) cua viet*.