Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hang di » hang doi, hang vi, hang dien
hanh di » hanh vi, hanh de, danh di
cau luc » cau truc, cau phuc
hieu va » lieu va, hieu qua
hieu ve » hieu van
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
luc va » duc va, tuc va, loc va

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 ky nang xa hoi. ((hieu ve) or (hieu va)) cau luc va ((hanh di) OR (hang di)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang xa hoi. ((hieu ve) OR (hieu va)) cau luc va ((hanh di) OR (hang di)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang xa hoi. ((hieu ve) or (hieu va)) cau luc va ((hanh di) OR (hang di)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. ((hieu ve) or (hieu va)) cau luc va ((hanh di) OR (hang di)) cua tre*.