Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
doan van » doan va, hoang van, luan van
tu sach » thu sach, su sach, te sach
ty nang » ty xang, ty hang, ly nang
van cau » van dau, van hau, van chat
van cua » vang cua, ban cua, dan cua
luc va » duc va, loc va
tuc va » thuc va, truc va, tuc xa
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) OR (ky nang)) x ho. hieu van cau ((luc va) or (tuc va)) doan van cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty nang) OR (ky nang)) x ho. hieu van cau ((luc va) OR (tuc va)) doan van cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ty nang) OR (ky nang)) x ho. hieu van cau ((luc va) or (tuc va)) doan van cua te".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ty nang) OR (ky nang)) x ho. hieu van cau ((luc va) or (tuc va)) doan van cua te*.