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 le » hieu ve, hieu he, hieu ly
dat duc » dat duoc, dao duc, dat doc
danh vi » hanh vi, danh di, danh va
dinh vi » dinh ve, dinh viet, dinh tri
le dat » le dan, de dat, le dac
cua te » cua tu
x hoi » xa hoi, o hoi, 5 hoi

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) OR (x ho)). hieu le dat duc va ((danh vi) or (dinh vi)) cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ((x hoi) OR (x ho)). hieu le dat duc va ((danh vi) OR (dinh vi)) cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang ((x hoi) OR (x ho)). hieu le dat duc va ((danh vi) or (dinh vi)) cua te".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ((x hoi) OR (x ho)). hieu le dat duc va ((danh vi) or (dinh vi)) cua te*.