Perhaps you should try some spelling variations:
hanh nhan » thanh nhan, danh nhan, anh nhan
hanh than » hanh han, hanh phan, nhanh thanh
thien van » thi van
tu sach » thu sach, su sach, te sach
cac duc » cac du, cao duc, cac dac
duc van » duc va, duc tan, duc manh
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
nang o » nang co, nang ho, nang ro
o hai » co hai, so hai, o lai

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 ky nang o hai. ((hieu ve) or (thien van)) cac duc van ((hanh than) OR (hanh nhan)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang o hai. ((hieu ve) OR (thien van)) cac duc van ((hanh than) OR (hanh nhan)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang o hai. ((hieu ve) or (thien van)) cac duc van ((hanh than) OR (hanh nhan)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang o hai. ((hieu ve) or (thien van)) cac duc van ((hanh than) OR (hanh nhan)) cua tre*.