Perhaps you should try some spelling variations:
va hanh » van hanh, va thanh, va danh
cao duc » dao duc, cao suc, giao duc
sach tu » sach thu, sach ty, sach uu
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
cach tu » cach thuc
cuu tre » cua tre, cau tren, cau treo
va cao » va cac, va co, va dao
cua cu » cua chu, cua cau, cua su

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 tu) or (cach tu)) nang xa hoi. hieu va cao duc va hanh vi ((cua cu) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach tu) OR (cach tu)) nang xa hoi. hieu va cao duc va hanh vi ((cua cu) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: te ((sach tu) or (cach tu)) nang xa hoi. hieu va cao duc va hanh vi ((cua cu) or (cuu tre))*.