Perhaps you should try some spelling variations:
doanh van » doan van, doanh va, doanh ban
cau tren » cu tren, dau tren, ca tren
tay tang » tay lang, tay trung, tay quang
danh vai » danh sai, danh va, dang van
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
ty tang » ty xang, ty hang, ky tang
nam xuc » cam xuc, nam xua, nam thuc
xuc va » duc va, tuc va, luc 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 tang) OR (tay tang)) xa hoi. hieu van nam xuc va ((danh vai) or (doanh van)) cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty tang) OR (tay tang)) xa hoi. hieu van nam xuc va ((danh vai) OR (doanh van)) cau tren*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ty tang) OR (tay tang)) xa hoi. hieu van nam xuc va ((danh vai) or (doanh van)) cau tren*".