Perhaps you should try some spelling variations:
tan hanh » tan thanh, tang hanh, toan hanh
te sach » toc sach
cam duc » cam xuc, cao duc, pham duc
hieu ve » hieu va, hieu van
cuu tre » cua tre, cau tren, cau treo
su sach » so sach, vu sach
ve cam » ve cham, ve cac, va cam
vi cuu » vi luu, vinh cuu
o hoi » co hoi, o hai, o hoa
o hoc » co hoc, mo hoc, so hoc

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) OR (o hoc)). hieu ve cam duc tan hanh vi cuu tre~.
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (su sach)) ky nang ((o hoi) or (o hoc)). hieu ve cam duc tan hanh vi cuu tre*.