Perhaps you should try some spelling variations:
dang xay » dang van, van xay
lang xa » lang ha, lang van
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
cac toc » cac toi, cac nuoc, cac thoi
da nang » cam nang, kha nang, cao nang
su sach » so sach, vu sach
ve cac » va cac, vien cac
thiet » thieu

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 ky ((lang xa) OR (dang xay)) hoi. hieu ve cac toc ((van dong) or (da nang)) hoi va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((lang xa) OR (dang xay)) hoi. hieu ve cac toc ((van dong) OR (da nang)) hoi va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((lang xa) OR (dang xay)) hoi. hieu ve cac toc ((van dong) or (da nang)) hoi va thiet".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((lang xa) OR (dang xay)) hoi. hieu ve cac toc ((van dong) or (da nang)) hoi va thiet*.