Perhaps you should try some spelling variations:
doanh va » doan va, doanh tai, doanh cua
tu sach » thu sach, su sach, te sach
ky lang » ky nang, ky tang, tay lang
ky dang » ky nang, ky danh
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
ve cam » ve cham, ve cac, va cam
luc va » tuc va, loc va
va cua » va chua, via cua, ca cua

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 ((ky lang) or (ky dang)) xa hoi. hieu ve cam ((luc va) OR (duc va)) doanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky lang) OR (ky dang)) xa hoi. hieu ve cam ((luc va) OR (duc va)) doanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky lang) or (ky dang)) xa hoi. hieu ve cam ((luc va) OR (duc va)) doanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky lang) or (ky dang)) xa hoi. hieu ve cam ((luc va) OR (duc va)) doanh va cua tre*.