Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
toc sach » hoc sach, doc sach, nuoc sach
cac thu » cach thuc, cac thoi
ty hang » ly hang, ty xang, thi hang
hang xa » hoang xa, hang va, hang ca
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
vi cua » vai cua, di cua
cua te » cua tu
ca thu » cam thu, ca tru, va thu

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 (thuoc sach)) ty hang xa hoi. hieu va ((ca thu) or (cac thu)) va hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (thuoc sach)) ty hang xa hoi. hieu va ((ca thu) OR (cac thu)) va hanh vi cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (thuoc sach)) ty hang xa hoi. hieu va ((ca thu) or (cac thu)) va hanh vi cua te".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (thuoc sach)) ty hang xa hoi. hieu va ((ca thu) or (cac thu)) va hanh vi cua te*.