Perhaps you should try some spelling variations:
tu sach » thu sach, te sach, tu cach
va hanh » van hanh, va thanh, va danh
tu hang » thu hang, tu hanh, tu hung
su sach » so sach, vu sach
hang o » hang do, hang o2, hoang o
ve cac » va cac, vien cac
va cao » va cac, va co, va dao
vi cua » vai cua, di cua
cua te » cua tu
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) OR (su sach)) tu hang o hoi. hieu ((ve cac) or (va cao)) duc va hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) tu hang o hoi. hieu ((ve cac) OR (va cao)) duc va hanh vi cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (su sach)) tu hang o hoi. hieu ((ve cac) or (va cao)) duc va hanh vi cua te".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (su sach)) tu hang o hoi. hieu ((ve cac) or (va cao)) duc va hanh vi cua te*.