Perhaps you should try some spelling variations:
hac thuc » hoc thuc, ha thuc, thach thuc
va thanh » gia thanh, ban thanh, le thanh
va tinh » may tinh
vu sach » vu bach, su sach, vu khach
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
va hac » van hac, va khac, va cac
y nang » ky nang, ly nang, may nang
v nang » va nang, vu nang, van nang
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach ((y nang) OR (v nang)) xa hoi. hieu va hac thuc ((va thanh) or (va tinh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ((y nang) OR (v nang)) xa hoi. hieu va hac thuc ((va thanh) OR (va tinh)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ((y nang) OR (v nang)) xa hoi. hieu va hac thuc ((va thanh) or (va tinh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: vu sach ((y nang) OR (v nang)) xa hoi. hieu va hac thuc ((va thanh) or (va tinh)) vi cua tre*.