Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
va triet » va thiet, va trien, ve triet
tham soc » cham soc, tham nuoc, thai son
hieu van » hieu va, thien van, lieu va
van tham » van thanh, van tuan, van chat
lang xa » lang ha, dang xay, lang van
sach ky » sac ky, sach y, sach ty
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
nang xa » nang x, nang ma, mang xa
tu sach » thu sach, su sach, te sach
soc va » hoc va, loc va, doc va

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 ky ((nang xa) or (lang xa)) hoi. hieu van tham soc va hanh di ((va triet) or (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (lang xa)) hoi. hieu van tham soc va hanh di ((va triet) OR (cua viet)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang xa) or (lang xa)) hoi. hieu van tham soc va hanh di ((va triet) or (cua viet))*.