Perhaps you should try some spelling variations:
cac thuc » cach thuc, cac thu, can thuc
thanh va » thanh van, hanh va, thanh ha
thanh vi » hanh vi, thanh ve, nhanh vi
thuc va » thuc vat, thuc dan, thuc day
so sach » bo sach, co sach, hoc sach
qua cac » cua cac
nang xa » nang x, lang xa, nang ma
ly nang » ky nang, ly hang, ly vang
so sanh » do sanh
cua tre » cua te, cuu tre, cua triet

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) or (so sanh)) ly nang xa hoi. hieu qua cac thuc va ((thanh vi) OR (thanh va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (so sanh)) ly nang xa hoi. hieu qua cac thuc va ((thanh vi) OR (thanh va)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((so sach) or (so sanh)) ly nang xa hoi. hieu qua cac thuc va ((thanh vi) OR (thanh va)) cua tre".
• Adding a wildcard symbol may retrieve word variants: ((so sach) or (so sanh)) ly nang xa hoi. hieu qua cac thuc va ((thanh vi) OR (thanh va)) cua tre*.