Perhaps you should try some spelling variations:
hieu hien » bieu hien, dieu hien, chieu chien
hieu vien » hieu viec, thieu nien, hieu tieng
thu sach » tu sach, thuat sach, thuoc sach
cua viet » ca viet, hoa viet, cua vat
nang ma » tang ma, sang ma, nang cao
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
danh vi » hanh vi, danh di, danh va
dinh vi » dinh ve, dinh viet, dinh tri
ma hoi » mai hoi, xa hoi, ma hoa
xuc va » duc va, tuc va, luc va

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

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