Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
sach ly » sach y, sach lo, sach ty
ly nang » ky nang, ly hang, ly vang
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
cac tac » cac toc, cac bac, cac dac
tac van » tac vang, cac van, tac va
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ly nang xa hoi. ((hieu ve) or (lieu va)) cac tac van hanh vi ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ly nang xa hoi. ((hieu ve) OR (lieu va)) cac tac van hanh vi ((cua tre) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: su sach ly nang xa hoi. ((hieu ve) or (lieu va)) cac tac van hanh vi ((cua tre) or (cuu tre))*.