Perhaps you should try some spelling variations:
hieu luc » hieu luat, hieu qua
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
hieu tuc » hieu thuc, hieu thuoc, lieu thuc
cham xuc » cam xuc, chat xuc, cham soc
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
hang xa » hoang xa, hang va, hang ca
ty hang » ly hang, ty xang, thi hang
cua tre » cua te, cuu tre, cua triet
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 hang xa hoi. ((hieu tuc) OR (hieu luc)) cham xuc ((van hanh) or (ban hanh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty hang xa hoi. ((hieu tuc) OR (hieu luc)) cham xuc ((van hanh) OR (ban hanh)) vi cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty hang xa hoi. ((hieu tuc) OR (hieu luc)) cham xuc ((van hanh) or (ban hanh)) vi cua tre*".