Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
quoc ban » quoc bao, quoc lan, quoc quan
cua viet » ca viet, hoa viet, cua vat
vu cham » va cham, vu kham, tu cham
sach ty » sach y, sach tu, sach thu
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
hanh di » hanh vi, hanh de, danh di
hang di » hang doi, hang vi, hang dien
ve cac » va cac, vien cac

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 ty nang xa hoi. hieu ((vu cham) or (ve cac)) quoc ban ((hanh di) or (hang di)) cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ty nang xa hoi. hieu ((vu cham) OR (ve cac)) quoc ban ((hanh di) OR (hang di)) cua viet.
• Adding a wildcard symbol may retrieve word variants: hoc sach ty nang xa hoi. hieu ((vu cham) or (ve cac)) quoc ban ((hanh di) or (hang di)) cua viet*.