Perhaps you should try some spelling variations:
hanh than » hanh nhan, hanh phan, nhanh thanh
hanh han » hanh nhan, hanh phan, hanh san
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
cac vuc » cac nuoc, cac vung, cac cuoc
vuc van » duc van, luc van, thuc van
van cac » van hac, van cau, van bac
cua tre » cua te, cuu tre, cua triet
nang o » nang co, nang ho, nang ro
tu san » thu san, tu ban, tu can
o lai » o lao

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (tu san)) ky nang o lai. hieu van cac vuc van ((hanh than) OR (hanh han)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (tu san)) ky nang o lai. hieu van cac vuc van ((hanh than) OR (hanh han)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (tu san)) ky nang o lai. hieu van cac vuc van ((hanh than) OR (hanh han)) cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (tu san)) ky nang o lai. hieu van cac vuc van ((hanh than) OR (hanh han)) cua tre*.