Perhaps you should try some spelling variations:
te sach » toc sach
dua ban » dia ban, cua ban, qua ban
duc ban » duc tan, duc van, duc man
hieu ve » hieu va, hieu van
cuu tre » cua tre, cau tren, cau treo
su sach » so sach, vu sach
nang o » nang co, nang ho, nang ro
vi cuu » vi luu, vinh cuu
ve cam » ve cham, ve cac, va cam
o hoi » co hoi, o hoc, o hai

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (su sach)) ky nang o hoi. hieu ve cam ((duc ban) OR (dua ban)) hanh vi cuu tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (su sach)) ky nang o hoi. hieu ve cam ((duc ban) OR (dua ban)) hanh vi cuu tre~".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (su sach)) ky nang o hoi. hieu ve cam ((duc ban) OR (dua ban)) hanh vi cuu tre*.