Perhaps you should try some spelling variations:
vat thanh » dat thanh, gat thanh, tat thanh
pham duy » pham duc
sach tu » sach thu, cach tu, sach uu
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
di su » doi su, da su, de su
ki su » ky 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 tu) or (sach ty)) nang xa hoi. hieu ve pham duy vat thanh ((di su) OR (ki 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 vat thanh ((di su) OR (ki 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 vat thanh ((di su) OR (ki su)) triet*".