Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
hang tai » hang va
vat hanh » vat thanh, van hanh, va hanh
sach lo » sach dao, sach doi, sach hoi
su sach » so sach, vu sach
hieu vu » hieu va, hieu ve, hieu su
vu pham » su pham, vi pham, vu kham
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: su sach lo ((hang tai) OR (dung tai)) hai. hieu vu pham thuc vat hanh ((di su) or (ki su)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach lo ((hang tai) OR (dung tai)) hai. hieu vu pham thuc vat hanh ((di su) OR (ki su)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach lo ((hang tai) OR (dung tai)) hai. hieu vu pham thuc vat hanh ((di su) or (ki su)) triet".
• Adding a wildcard symbol may retrieve word variants: su sach lo ((hang tai) OR (dung tai)) hai. hieu vu pham thuc vat hanh ((di su) or (ki su)) triet*.