Perhaps you should try some spelling variations:
vu khach » vu khanh, vu khac, vay khach
ban hanh » ban hang
te sach » toc sach
vu sach » vu bach, su sach
hieu ve » hieu va, hieu van
ve pham » vi pham, v pham, ve phan
duc ban » duc tan, duc van, dua ban
cuu tre » cua tre, cau tren, cau treo
nang o » nang co, nang ho, nang ro
vi cuu » vi luu, vinh cuu
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: ((te sach) or (((vu sach) or (vu khach)))) ky nang o hoi. hieu ve pham duc ban hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (((vu sach) OR (vu khach)))) ky nang o hoi. hieu ve pham duc ban hanh vi cuu tre.
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (((vu sach) or (vu khach)))) ky nang o hoi. hieu ve pham duc ban hanh vi cuu tre*.