Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
hieu van » hieu va, thien van, lieu va
han tai » hang tai, nhan tai, van tai
cau luc » cau truc, cau phuc
van cau » van dau, van hau, van chat
ty hang » ly hang, ty xang, thi hang
ty nang » ky nang, ty xang, ly nang
cua tre » cua te, cuu tre, cua triet
luc va » duc va, tuc va, loc va

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

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