Perhaps you should try some spelling variations:
pham dung » pham dang, pham dong, pham hung
cua triet » cua viet, su triet
va triet » va thiet, va trien, ve triet
dung may » dung va, dung tai, mang may
sach tu » sach thu, cach tu, sach uu
tinh di » tinh doi, trinh di, tinh da
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 dung may tinh di ((cua triet) OR (va 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 dung may tinh di ((cua triet) OR (va 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 dung may tinh di ((cua triet) OR (va triet))".
• Adding a wildcard symbol may retrieve word variants: tu ((sach tu) or (sach ty)) nang xa hoi. hieu ve pham dung may tinh di ((cua triet) OR (va triet))*.