Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
thanh dai » thanh hai, thanh tai, thanh dat
nang mai » nang ma, nang tai, lang mai
sach ty » sach y, sach tu, sach thu
cua tre » cua te, cuu tre, dua tren
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
ty nang » ky nang, ty xang, ty hang
ve cac » va cac, vien cac
tuc va » thuc va, truc va, tuc xa
luc va » duc va, loc 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 mai hoi. hieu ve cac ((luc va) OR (tuc va)) thanh dai ((cua tre) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang mai hoi. hieu ve cac ((luc va) OR (tuc va)) thanh dai ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang mai hoi. hieu ve cac ((luc va) OR (tuc va)) thanh dai ((cua tre) or (cua triet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang mai hoi. hieu ve cac ((luc va) OR (tuc va)) thanh dai ((cua tre) or (cua triet))*.