Perhaps you should try some spelling variations:
thien van » thi van
va lang » va nang, hoa lang
sach ky » sac ky, sach y, sach ty
tu sach » thu sach, su sach, te sach
nang xa » lang xa, nang ma, mang xa
am hoc » ad hoc
de cua » le cua, te cua, dieu cua
van am » van nam, van lam, van dam
di cu » di cau, di cua, di du

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