Perhaps you should try some spelling variations:
danh cong » dang cong, hanh cong, anh cong
hieu van » hieu va, thien van, lieu va
cong cu » chung cu
van cac » van hac, van cau, van bac
tu sach » thu sach, su sach, te sach
mang xa » lang xa, mang may, dang xay
sach ky » sac ky, sach y, sach ty
xuc va » tuc va, luc va, xac va
cu tre » cu tren, cua tre, cuu tre

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 ((mang xa) or (nang x)) hoi. hieu van cac ((xuc va) OR (duc va)) danh cong cu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((mang xa) OR (nang x)) hoi. hieu van cac ((xuc va) OR (duc va)) danh cong cu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((mang xa) or (nang x)) hoi. hieu van cac ((xuc va) OR (duc va)) danh cong cu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((mang xa) or (nang x)) hoi. hieu van cac ((xuc va) OR (duc va)) danh cong cu tre*.