Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
toc sac » toc sach, toc san, hoc sach
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
hien te » tien te, hien tu, khien tu
hanh di » hanh de, hang di, danh di
sac ky » cac ky, sai ky
te cua » tue cua, le cua, de cua
bo va » bao va, do va, so va

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sac ky ((nang xa) or (lang xa)) hoi. hien te cua bo va ((hanh di) OR (hanh vi)) cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sac ky ((nang xa) OR (lang xa)) hoi. hien te cua bo va ((hanh di) OR (hanh vi)) cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sac ky ((nang xa) or (lang xa)) hoi. hien te cua bo va ((hanh di) OR (hanh vi)) cua triet".
• Adding a wildcard symbol may retrieve word variants: toc sac ky ((nang xa) or (lang xa)) hoi. hien te cua bo va ((hanh di) OR (hanh vi)) cua triet*.