Perhaps you should try some spelling variations:
vanh dai » van dai, vanh tai, lanh dao
sach ky » sach y, sach ty, sach kem
dai huu » dao huu, dai hau, dai thua
va vanh » va van, va danh, va hanh
cac luc » cau luc, coc luc, cac nuoc
hieu va » lieu va, hieu qua
huu tre » huu tri, cuu tre, huu them
nang ho » nang hoc, nang co, tang ho
nang ro » nang co, nang ra, nang rong
luc va » duc va, tuc va, loc va
sac ky » cac ky, sai ky

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) or (sac ky)) ((nang ro) OR (nang ho)) hoc. hieu va cac luc va vanh dai huu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sac ky)) ((nang ro) OR (nang ho)) hoc. hieu va cac luc va vanh dai huu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) or (sac ky)) ((nang ro) OR (nang ho)) hoc. hieu va cac luc va vanh dai huu tre*".