Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
kinh vi » dinh vi, kinh ve, kenh vi
va kinh » va tinh, qua kinh
cac toc » cac toi, cac nuoc, cac thoi
sach ty » sach y, sach tu, sach thu
hieu va » lieu va, hieu qua
tu sach » thu sach, su sach, te sach
nang xa » lang xa, nang ma, mang xa
cac hoc » cach hoc, cac hop, bac hoc
vi su » va su, ve su, ki su

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 ty ((nang xa) OR (nang x)) hoi. hieu va ((cac hoc) or (cac toc)) va kinh vi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((nang xa) OR (nang x)) hoi. hieu va ((cac hoc) OR (cac toc)) va kinh vi su triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty ((nang xa) OR (nang x)) hoi. hieu va ((cac hoc) or (cac toc)) va kinh vi su triet*".