Perhaps you should try some spelling variations:
dang xay » dang van, van xay
hieu van » thien van, lieu va, hieu ve
hanh tri » thanh tri, hanh tai, hanh trinh
su sach » so sach, vu sach
lang xa » lang ha, lang van
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
luc va » duc va, tuc va, loc va

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