Perhaps you should try some spelling variations:
cua triet » cua viet, va triet
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
tinh lap » trinh lap, tinh lao, dinh lap
su triet » su viet, su tien, ve triet
su sach » so sach, vu sach
ky lang » ky nang, ky tang, tay lang
ky dang » ky nang, ky danh
hieu va » lieu va, hieu qua
va tinh » may tinh

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ((ky lang) or (ky dang)) xa hoi. hieu va cac nuoc va tinh lap ((cua triet) OR (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ky lang) OR (ky dang)) xa hoi. hieu va cac nuoc va tinh lap ((cua triet) OR (su triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ky lang) or (ky dang)) xa hoi. hieu va cac nuoc va tinh lap ((cua triet) OR (su triet))".
• Adding a wildcard symbol may retrieve word variants: su sach ((ky lang) or (ky dang)) xa hoi. hieu va cac nuoc va tinh lap ((cua triet) OR (su triet))*.