Perhaps you should try some spelling variations:
thieu nien » thien nhien
nien bach » vien bach, dien sach, mien bac
cua triet » cua viet, su triet, va triet
dinh vai » dinh van, dinh vi, dinh va
ty nang » ky nang, ty xang, ty hang
sach ty » sach y, sach tu, sach thu
bach lo » sach lo, bach hoa, bach mao
va dinh » van dinh, va kinh, va tinh
cua tre » cua te, cuu tre, dua tren
tu sach » thu sach, su sach, te sach
o hoi » co hoi, o hai, o hoa
o hoc » co hoc, mo hoc, so hoc
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 ty nang ((o hoi) OR (o hoc)). thieu nien bach lo 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 ((o hoi) OR (o hoc)). thieu nien bach lo 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 ((o hoi) OR (o hoc)). thieu nien bach lo va dinh vai ((cua tre) or (cua triet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ((o hoi) OR (o hoc)). thieu nien bach lo va dinh vai ((cua tre) or (cua triet))*.