Perhaps you should try some spelling variations:
hanh dao » lanh dao, thanh dat, thanh dam
hanh dai » hanh tai, vanh dai, thanh dat
so sach » so sanh, bo sach, co sach
luc van » luoc van, luu van, duc van
cau luc » cau truc, cau phuc
hieu ve » hieu va, hieu van
tai hoa » tai khoa, thai hoa, thi hoa
cua tre » cua te, cuu tre, cua triet
y nang » ly nang, v nang, may nang
ve cau » ke cau, va cau, ve cac

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 ((y nang) or (ky nang)) tai hoa. hieu ve cau luc van ((hanh dai) OR (hanh dao)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ((y nang) OR (ky nang)) tai hoa. hieu ve cau luc van ((hanh dai) OR (hanh dao)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ((y nang) or (ky nang)) tai hoa. hieu ve cau luc van ((hanh dai) OR (hanh dao)) cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach ((y nang) or (ky nang)) tai hoa. hieu ve cau luc van ((hanh dai) OR (hanh dao)) cua tre*.