Perhaps you should try some spelling variations:
thieu nien » thien nhien
nien cac » vien cac, dien cac, bien cac
ve triet » va trien, su triet
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
nang xa » nang x, lang xa, nang ma
toc van » hoc van, tac van, oc van
su viet » so viet

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 ty nang xa hoi. thieu nien cac ((toc van) OR (toc san)) hanh vi ((su viet) or (ve triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang xa hoi. thieu nien cac ((toc van) OR (toc san)) hanh vi ((su viet) OR (ve triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty nang xa hoi. thieu nien cac ((toc van) OR (toc san)) hanh vi ((su viet) or (ve triet))".
• Adding a wildcard symbol may retrieve word variants: su sach ty nang xa hoi. thieu nien cac ((toc van) OR (toc san)) hanh vi ((su viet) or (ve triet))*.