Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
toc sach » hoc sach, doc sach, thuoc sach
thuc day » thuc dan, thuc vat
dat cua » dai cua, day cua, mat cua
dan dat » dung dat, dong dat, dinh dat
thuc va » thuc vat, thuc dan
hieu ve » hieu va, hieu van
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
ve chat » va chat, van chat

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)) ky lang xa hoi. hieu ve chat ((thuc va) OR (thuc day)) dan dat cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky lang xa hoi. hieu ve chat ((thuc va) OR (thuc day)) dan dat cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) ky lang xa hoi. hieu ve chat ((thuc va) OR (thuc day)) dan dat cua triet".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ky lang xa hoi. hieu ve chat ((thuc va) OR (thuc day)) dan dat cua triet*.