Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
cam thuc » am thuc, nam thuc, cam thu
hanh tai » thanh tai, hang tai, han tai
hieu van » hieu va, thien van, lieu va
so sach » so sanh, bo sach, co sach
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
van cam » van nam, van lam, van cau
sach lo » sach dao, sach doi, sach hoi
hang ca » hang va, nang cao, hang tai
hang xa » hoang xa, hang va, lang xa
cu tren » tu tren, dua tren

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: so sach lo ((hang xa) or (hang ca)) hoi. hieu van cam thuc va hanh tai ((cua triet) or (cu tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach lo ((hang xa) OR (hang ca)) hoi. hieu van cam thuc va hanh tai ((cua triet) OR (cu tren)).
• Adding a wildcard symbol may retrieve word variants: so sach lo ((hang xa) or (hang ca)) hoi. hieu van cam thuc va hanh tai ((cua triet) or (cu tren))*.