Perhaps you should try some spelling variations:
cua triet » su triet, va triet
cua viet » ca viet, hoa viet, cua vat
cam thuc » am thuc, nam thuc, cam thu
hanh lai » hanh lam, hanh tai, thanh lap
van hanh » van thanh, ban hanh, van anh
sach tai » sach bai, sach tham, sach dao
thuc van » thuc vat, thuc dan, thuc va
tu sach » thu sach, su sach, te sach
hang ca » hang va, nang cao, hang tai
hang xa » hoang xa, hang va, lang xa
hieu ve » hieu va, hieu van
ve cam » ve cham, ve cac, va cam

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 tai ((hang xa) OR (hang ca)) hoi. hieu ve cam thuc van hanh lai ((cua triet) or (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach tai ((hang xa) OR (hang ca)) hoi. hieu ve cam thuc van hanh lai ((cua triet) OR (cua viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach tai ((hang xa) OR (hang ca)) hoi. hieu ve cam thuc van hanh lai ((cua triet) or (cua viet))".
• Adding a wildcard symbol may retrieve word variants: tu sach tai ((hang xa) OR (hang ca)) hoi. hieu ve cam thuc van hanh lai ((cua triet) or (cua viet))*.