Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
hieu va » hieu qua
danh vi » hanh vi, danh di, danh va
dinh vi » dinh ve, dinh viet, dinh tri
cua tre » cua te, cuu tre, cua triet
x hoi » xa hoi, o hoi, x ho

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 x hoi. ((hieu va) OR (lieu va)) pham duc va ((danh vi) OR (dinh vi)) cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang x hoi. ((hieu va) OR (lieu va)) pham duc va ((danh vi) OR (dinh vi)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang x hoi. ((hieu va) OR (lieu va)) pham duc va ((danh vi) OR (dinh vi)) cua tre*.