Perhaps you should try some spelling variations:
hac thuc » hoc thuc, ha thuc, thach thuc
va thanh » gia thanh, ban thanh, le thanh
vu sach » vu bach, su sach, vu khach
va tinh » may tinh
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
vi cua » vai cua, di cua
va hac » van hac, va khac, va cac

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 ky ((nang xa) OR (nang ma)) 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 ky ((nang xa) OR (nang ma)) 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 ky ((nang xa) OR (nang ma)) hoi. hieu va hac thuc ((va thanh) or (va tinh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: vu sach ky ((nang xa) OR (nang ma)) hoi. hieu va hac thuc ((va thanh) or (va tinh)) vi cua tre*.