Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu ve » hieu van
hieu va » lieu va, hieu qua
xuc van » duc van, luc van, vuc van
cua tu » cua tuc, cua su, cua te
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: toc sach ky nang xa hoi. ((hieu ve) OR (hieu va)) cam xuc van hanh vi ((cua tu) or (cua cu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang xa hoi. ((hieu ve) OR (hieu va)) cam xuc van hanh vi ((cua tu) OR (cua cu)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky nang xa hoi. ((hieu ve) OR (hieu va)) cam xuc van hanh vi ((cua tu) or (cua cu))".
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang xa hoi. ((hieu ve) OR (hieu va)) cam xuc van hanh vi ((cua tu) or (cua cu))*.