Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
dieu cua » dieu tra
dieu can » dieu hanh, tiep can
huu phuc » huu thuc, huu phach, huu duc
hieu su » hieu sau, tieu su, hieu so
sach ky » sac ky, sach y, sach ty
phuc va » phuc vu, thuc va, chuc va
hieu vu » hieu va, hieu ve, dieu vu
nang xa » nang x, lang xa, nang ma
va dac » va cac, va dao, va dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach ky nang xa hoi. ((hieu vu) or (hieu su)) huu phuc va dac ((dieu can) OR (dieu cua)) treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ky nang xa hoi. ((hieu vu) OR (hieu su)) huu phuc va dac ((dieu can) OR (dieu cua)) treo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ky nang xa hoi. ((hieu vu) or (hieu su)) huu phuc va dac ((dieu can) OR (dieu cua)) treo".
• Adding a wildcard symbol may retrieve word variants: hoc sach ky nang xa hoi. ((hieu vu) or (hieu su)) huu phuc va dac ((dieu can) OR (dieu cua)) treo*.