Perhaps you should try some spelling variations:
cuon sach » duong sach, cuoc cach, nuoc sach
co sach » bo sach, hoc sach
hanh va » hang va
duc van » duc va, duc tan, duc manh
cam duc » cam xuc, cao duc, pham duc
cua tre » cua te, cuu tre, cua triet
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
va cam » va cham, va cac, va cao

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((co sach) OR (cuon sach)) ty nang xa hoi. lieu va cam duc van ((hanh vi) or (hanh va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((co sach) OR (cuon sach)) ty nang xa hoi. lieu va cam duc van ((hanh vi) OR (hanh va)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((co sach) OR (cuon sach)) ty nang xa hoi. lieu va cam duc van ((hanh vi) or (hanh va)) cua tre".
• Adding a wildcard symbol may retrieve word variants: ((co sach) OR (cuon sach)) ty nang xa hoi. lieu va cam duc van ((hanh vi) or (hanh va)) cua tre*.