Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien cac » vien bach, vien dai, vien da
cua viet » ca viet, cua vat, cua dieu
tu sach » thu sach, su sach, te sach
ty nang » ky nang, ty xang, ty hang
nang ma » tang ma, sang ma, nang cao
sach ty » sach y, sach tu, sach thu
xuc va » duc va, tuc va, xac va
luc va » duc va, tuc va, loc va
ma hoi » mai hoi, xa hoi, ma hoa

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 ma hoi. hieu vien cac ((xuc va) or (luc va)) hanh vi ((cua viet) OR (hoa viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ma hoi. hieu vien cac ((xuc va) OR (luc va)) hanh vi ((cua viet) OR (hoa viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang ma hoi. hieu vien cac ((xuc va) or (luc va)) hanh vi ((cua viet) OR (hoa viet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ma hoi. hieu vien cac ((xuc va) or (luc va)) hanh vi ((cua viet) OR (hoa viet))*.