Perhaps you should try some spelling variations:
van triet » va triet, van thiet, van trieu
toc sach » hoc sach, doc sach, thuoc sach
sach thu » sach thue, sach thieu, sach tham
thu hanh » thuc hanh, thu thanh, thuy hanh
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
cac toc » cac toi, cac thoi
xa hanh » xa thanh, xa khanh, va hanh
hanh va » hang va, hanh vi
ca hoi » cua hoi, xa hoi, co hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach thu hanh ((ca hoi) or (cau hoi)). lieu va ((cac nuoc) or (cac toc)) xa hanh va van triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach thu hanh ((ca hoi) OR (cau hoi)). lieu va ((cac nuoc) OR (cac toc)) xa hanh va van triet.
• Adding a wildcard symbol may retrieve word variants: toc sach thu hanh ((ca hoi) or (cau hoi)). lieu va ((cac nuoc) or (cac toc)) xa hanh va van triet*.