Perhaps you should try some spelling variations:
ninh duc » minh duc, dinh duc, tinh duc
cam luc » cam xuc, cau luc
cuu tre » cau tren, cau treo
va ninh » van ninh, va kinh, va tinh
cua tre » cua te, cua triet, dua tren
sach ky » sach y, sach ty, sach kem
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
luc va » duc va, tuc va, loc va
sac ky » cac ky, sai ky
va cam » va cham, va cac, va cao

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