Perhaps you should try some spelling variations:
cau triet » cau trieu, su triet, cua triet
kho tang » cao tang
toc sach » hoc sach, doc sach, thuoc sach
ky tang » ky nang, ky dang, ky trong
thuc va » thuc vat, thuc dan, thuc day
dan van » dang van, doan van, dao van
van cau » van dau, van hau, van chat
va nam » van nam, va nay
va dan » ca dan, va dao, va dau

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 ((ky tang) or (kho tang)) xa hoi. hieu ((va nam) or (ha nam)) thuc va dan van cau triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ky tang) OR (kho tang)) xa hoi. hieu ((va nam) OR (ha nam)) thuc va dan van cau triet.
• Adding a wildcard symbol may retrieve word variants: toc sach ((ky tang) or (kho tang)) xa hoi. hieu ((va nam) or (ha nam)) thuc va dan van cau triet*.