Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
cua triet » cua viet, su triet, va triet
nang mai » nang ma, nang tai, lang mai
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu va, hieu van
ve cac » va cac, vien cac
luc va » tuc va, loc va
cua te » cua tu

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 (duc va)) thanh dai ((cua te) 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 (duc va)) thanh dai ((cua te) 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 (duc va)) thanh dai ((cua te) or (cua triet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang mai hoi. hieu ve cac ((luc va) OR (duc va)) thanh dai ((cua te) or (cua triet))*.