Perhaps you should try some spelling variations:
phan duc » pham duc, phan tu, phan dau
hanh tai » thanh tai, hang tai, han tai
van hanh » van thanh, ban hanh, van anh
sach thu » sach thue, sach thieu, sach tham
hieu van » hieu va, thien van, lieu va
pham duy » pham duc
tai cua » thai cua, tai cuc, tri cua
sach tu » cach tu, sach ty, sach uu
x hoi » xa hoi, o hoi, x ho

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 tu) or (sach thu)) nang x hoi. hieu van ((phan duc) or (pham duy)) van hanh tai cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach tu) OR (sach thu)) nang x hoi. hieu van ((phan duc) OR (pham duy)) van hanh tai cua vat.
• Adding a wildcard symbol may retrieve word variants: tu ((sach tu) or (sach thu)) nang x hoi. hieu van ((phan duc) or (pham duy)) van hanh tai cua vat*.