Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
trinh di » trinh do, trinh dien, trinh dinh
pham duy » pham duc
sach tu » sach thu, cach tu, sach uu
tinh di » tinh doi, tinh da, tin di
duy may » duy mai, dung may, duy thay
hieu ve » hieu va, hieu van
nang xa » nang x, lang xa, nang ma
sach ty » sach y, sach thu, xach tay
ve pham » vi pham, v pham, ve phan

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 tu) or (sach ty)) nang xa hoi. hieu ve pham duy may ((tinh di) OR (trinh di)) su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach tu) OR (sach ty)) nang xa hoi. hieu ve pham duy may ((tinh di) OR (trinh di)) su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach tu) or (sach ty)) nang xa hoi. hieu ve pham duy may ((tinh di) OR (trinh di)) su triet".
• Adding a wildcard symbol may retrieve word variants: tu ((sach tu) or (sach ty)) nang xa hoi. hieu ve pham duy may ((tinh di) OR (trinh di)) su triet*.