Perhaps you should try some spelling variations:
may nang » may nong, ky nang, cam nang
su sach » so sach, vu sach
hang vi » hang va, hanh vi, khang voi
hang di » hang doi, hang dien, hang dich
cac tuc » cac toc, cac tu, cac tac
hieu va » lieu va, hieu qua
tuc va » thuc va, truc va, tuc xa
v nang » va nang, vu nang, van nang
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: su sach ((may nang) or (v nang)) x hoi. hieu va cac tuc va ((hang di) OR (hang vi)) cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((may nang) OR (v nang)) x hoi. hieu va cac tuc va ((hang di) OR (hang vi)) cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((may nang) or (v nang)) x hoi. hieu va cac tuc va ((hang di) OR (hang vi)) cua vat".
• Adding a wildcard symbol may retrieve word variants: su sach ((may nang) or (v nang)) x hoi. hieu va cac tuc va ((hang di) OR (hang vi)) cua vat*.