Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
doanh va » doan va, doanh tai, doanh cua
va doanh » van doanh, vay doanh, va danh
hieu van » hieu va, thien van, lieu va
cam luc » cam xuc, cau luc
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va
ky danh » ky anh, ky dang
ky lang » ky nang, ky dang, ky tang
luc va » duc 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: thu sach ((ky lang) or (ky danh)) xa hoi. ((hieu ve) OR (hieu van)) cam luc va doanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((ky lang) OR (ky danh)) xa hoi. ((hieu ve) OR (hieu van)) cam luc va doanh va cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((ky lang) or (ky danh)) xa hoi. ((hieu ve) OR (hieu van)) cam luc va doanh va cua tre*".