Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hieu vien » hieu hien, hieu viec, thieu nien
bach hoa » bach khoa, bach ha, cach hoan
dinh vai » dinh van, dinh vi, dinh va
cua tre » cua te, cuu tre, dua tren
va dinh » van dinh, va kinh, va tinh
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
bach lo » sach lo, bach mao
ty nang » ky nang, ty xang, ty hang
x hoi » xa hoi, o hoi, x ho

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 x hoi. hieu vien ((bach lo) OR (bach hoa)) va dinh vai ((cua tre) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang x hoi. hieu vien ((bach lo) OR (bach hoa)) va dinh vai ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang x hoi. hieu vien ((bach lo) OR (bach hoa)) va dinh vai ((cua tre) or (cua triet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang x hoi. hieu vien ((bach lo) OR (bach hoa)) va dinh vai ((cua tre) or (cua triet))*.