Perhaps you should try some spelling variations:
sach thi » sach thu, sach tai, sach tham
day hanh » day nhanh, day thanh, dao hanh
thuc day » thuc dan, thuc vat
cam thuc » am thuc, nam thuc, cam thu
hieu ve » hieu va, hieu van
hanh xa » hanh va, hanh ma, hanh xu
ve cam » ve cham, ve cac, va cam
lam va » nam va, dam va, lam ha
nam ha » nam a, nam va, nam da

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 thi) OR (sach thieu)) hanh xa hoi. hieu ve cam thuc day hanh ((lam va) or (nam ha)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach thi) OR (sach thieu)) hanh xa hoi. hieu ve cam thuc day hanh ((lam va) OR (nam ha)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach thi) OR (sach thieu)) hanh xa hoi. hieu ve cam thuc day hanh ((lam va) or (nam ha)) triet".
• Adding a wildcard symbol may retrieve word variants: tu ((sach thi) OR (sach thieu)) hanh xa hoi. hieu ve cam thuc day hanh ((lam va) or (nam ha)) triet*.