Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
cau triet » cau trieu, su triet, va triet
thac tuc » thac toc, thai tuc, thach thuc
hieu va » lieu va, hieu qua
sach ky » sach y, sach ty, sach kem
va danh » va dinh, va dan, va hanh
danh va » doanh va, hanh va, anh va
va thac » van thac, va thuc, va tac
sac ky » cac ky, sai ky
tuc va » thuc va, truc va, tuc xa
x hoi » xa hoi, o hoi, x ho

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) OR (sac ky)) nang x hoi. hieu va thac tuc va danh va ((cau triet) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc ((sach ky) OR (sac ky)) nang x hoi. hieu va thac tuc va danh va ((cau triet) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc ((sach ky) OR (sac ky)) nang x hoi. hieu va thac tuc va danh va ((cau triet) or (cua triet))".
• Adding a wildcard symbol may retrieve word variants: toc ((sach ky) OR (sac ky)) nang x hoi. hieu va thac tuc va danh va ((cau triet) or (cua triet))*.