Perhaps you should try some spelling variations:
phan dau » phan tu, hang dau
tu sach » thu sach, te sach, tu cach
cac duc » cac du, cao duc, cac dac
duc van » duc va, duc tan, duc manh
cuu tre » cua tre, cau tren, cau treo
hieu ve » hieu va, hieu van
ty nang » ky nang, ty xang, ty hang
su sach » so sach, vu sach
ve cac » va cac, vien cac

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 (su sach)) ty nang x ho. hieu ve cac duc van ((thanh san) or (phan dau)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ty nang x ho. hieu ve cac duc van ((thanh san) OR (phan dau)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (su sach)) ty nang x ho. hieu ve cac duc van ((thanh san) or (phan dau)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (su sach)) ty nang x ho. hieu ve cac duc van ((thanh san) or (phan dau)) cuu tre*.