Perhaps you should try some spelling variations:
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
coc tuc » coc luc, hoc thuc, doc thuc
hieu va » lieu va, hieu qua
hieu ve » hieu van
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
cua tre » cua te, cuu tre, cua triet
va cua » va chua, via cua, ca 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 ky lang xa hoi. ((hieu ve) or (hieu va)) coc tuc ((va tinh) OR (may tinh)) va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky lang xa hoi. ((hieu ve) OR (hieu va)) coc tuc ((va tinh) OR (may tinh)) va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky lang xa hoi. ((hieu ve) or (hieu va)) coc tuc ((va tinh) OR (may tinh)) va cua tre".
• Adding a wildcard symbol may retrieve word variants: vu sach ky lang xa hoi. ((hieu ve) or (hieu va)) coc tuc ((va tinh) OR (may tinh)) va cua tre*.