Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
cam duc » cam xuc, cao duc, pham duc
sach ky » sac ky, sach ty, sach kem
hanh de » hanh ve, hanh kem
hang di » hang doi, hang vi, hang dien
nang o » nang co, nang ho, nang ro
va cam » va cham, va cac, va cao
o hai » co hai, so hai, o lai

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuat ((sach ky) OR (sach y)) nang o hai. lieu va cam duc va ((hanh de) or (hang di)) su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat ((sach ky) OR (sach y)) nang o hai. lieu va cam duc va ((hanh de) OR (hang di)) su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat ((sach ky) OR (sach y)) nang o hai. lieu va cam duc va ((hanh de) or (hang di)) su triet".
• Adding a wildcard symbol may retrieve word variants: thuat ((sach ky) OR (sach y)) nang o hai. lieu va cam duc va ((hanh de) or (hang di)) su triet*.