Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
hieu van » hieu va, thien van, lieu va
sach ty » sach y, sach tu, sach thu
sach ky » sac ky, sach y, sach kem
cam luc » cau luc
va hanh » van hanh, va thanh, va danh
nang o » nang co, nang ho, nang ro
vi cua » vai cua, di cua
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 ky) or (sach ty)) nang o hoi. hieu van ((cam luc) or (cam xuc)) va hanh vi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach ty)) nang o hoi. hieu van ((cam luc) OR (cam xuc)) va hanh vi cua viet.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sach ty)) nang o hoi. hieu van ((cam luc) or (cam xuc)) va hanh vi cua viet*.