Perhaps you should try some spelling variations:
sieu viet » su viet, dien viet, bien viet
hieu viec » nhieu viec, hieu ve, hieu hien
trinh vi » trinh va, trinh ve, trinh viet
sach ty » sach y, sach tu, sach thu
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet
xuc va » duc va, tuc va, xac va
luc va » duc va, tuc va, loc va
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ty nang xa hoi. ((hieu viec) or (sieu viet)) cam ((xuc va) OR (luc va)) trinh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang xa hoi. ((hieu viec) OR (sieu viet)) cam ((xuc va) OR (luc va)) trinh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang xa hoi. ((hieu viec) or (sieu viet)) cam ((xuc va) OR (luc va)) trinh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang xa hoi. ((hieu viec) or (sieu viet)) cam ((xuc va) OR (luc va)) trinh vi cua tre*.