Perhaps you should try some spelling variations:
thien van » thi van
dang xay » dang van, van xay
nang xa » nang x, lang xa, nang ma
sach ky » sac ky, sach y, sach ty
nam hoc » nam moc, nam hoi, am hoc
va hang » van hang, va nang, va lang
tu sach » thu sach, su sach, te sach
di cua » dai cua, doi cua, de cua
di cu » di cau, di du, da cu

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 ((nang xa) or (dang xay)) hoi. thien van nam hoc va hang ((di cu) OR (di cua)) tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (dang xay)) hoi. thien van nam hoc va hang ((di cu) OR (di cua)) tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang xa) or (dang xay)) hoi. thien van nam hoc va hang ((di cu) OR (di cua)) tren".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang xa) or (dang xay)) hoi. thien van nam hoc va hang ((di cu) OR (di cua)) tren*.