Perhaps you should try some spelling variations:
dang xay » dang van
hanh tai » thanh tai, hang tai, han tai
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
tai cua » thai cua, tai cuc, tri cua
sach ky » sac ky, sach y, sach ty
luc van » luoc van, luu van, duc van
cua te » cua tu
va dao » ca dao
va cao » va cac, va co, va bao

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 ((dang xay) or (van xay)) hoi. lieu ((va cao) OR (va dao)) luc van hanh tai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((dang xay) OR (van xay)) hoi. lieu ((va cao) OR (va dao)) luc van hanh tai cua te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((dang xay) or (van xay)) hoi. lieu ((va cao) OR (va dao)) luc van hanh tai cua te*".