Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
dua tren » dung tren
va triet » va thiet, va trien, cua triet
ve triet » va trien, su triet
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
bach lo » sach lo, bach hoa, bach mao
va dinh » van dinh, va kinh, va tinh
x hoi » xa hoi, o hoi, x ho
lo va » lo van, lao va, ly 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 x hoi. hieu vien bach lo va dinh van ((dua tren) or (((va triet) OR (ve triet))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang x hoi. hieu vien bach lo va dinh van ((dua tren) OR (((va triet) OR (ve triet)))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang x hoi. hieu vien bach lo va dinh van ((dua tren) or (((va triet) OR (ve triet))))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang x hoi. hieu vien bach lo va dinh van ((dua tren) or (((va triet) OR (ve triet))))*.