Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
hoc sach » hoc sinh, hoc cac, hoc anh
va tuong » va thong, xa truong, va phuong
cao hoi » cau hoi, co hoi, cao hoc
hieu va » lieu va, hieu qua
doi cua » dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
v nang » va nang, vu nang, van nang
cac tu » cac thu, cach tu, cac du

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sach) OR (hoc sach)) v nang cao hoi. hieu va cac tu ((va tuong) or (va thuong)) doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sach)) v nang cao hoi. hieu va cac tu ((va tuong) OR (va thuong)) doi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (hoc sach)) v nang cao hoi. hieu va cac tu ((va tuong) or (va thuong)) doi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (hoc sach)) v nang cao hoi. hieu va cac tu ((va tuong) or (va thuong)) doi cua tre*.