Perhaps you should try some spelling variations:
doanh va » doan va, doanh tai, doanh cua
su sach » vu sach
luu van » cuu van, luan van, luu hanh
luc van » luoc van, duc van, luc va
cua tre » cua te, cuu tre, cua triet
dang xa » dang xay, lang xa, dang ha
ky dang » ky nang, ky danh
so sach » so sanh, bo sach, co sach
va cua » va chua, via cua, ca cua
va cau » van cau, va cac, va dau

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (so sach)) ky dang xa hoi. lieu va cau ((luc van) OR (luu van)) doanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) ky dang xa hoi. lieu va cau ((luc van) OR (luu van)) doanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (so sach)) ky dang xa hoi. lieu va cau ((luc van) OR (luu van)) doanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) ky dang xa hoi. lieu va cau ((luc van) OR (luu van)) doanh va cua tre*.