Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
lam thuc » lam thuoc, am thuc, nam thuc
thuc dan » thuc hanh, hoc dan, thuc vat
dan hanh » dang hanh, dan khanh, dan thanh
hanh vai » hanh vi, hanh va, hanh tai
su triet » su viet, su tien, ve triet
xay hoi » xa hoi, tay hoi, cay phoi
van lam » van nam
ly van » le van, ly va, ly von
vai su » va su, van su, lai su

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) ly van xay hoi. hieu van lam thuc dan hanh vai su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ly van xay hoi. hieu van lam thuc dan hanh vai su triet.
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ly van xay hoi. hieu van lam thuc dan hanh vai su triet*.