Perhaps you should try some spelling variations:
loai nang » loai nam, luan nang, loai san
cua viet » ca viet, hoa viet, cua vat
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
hanh di » hanh vi, hanh de, hang di
tu sach » thu sach, su sach, te sach
lo nang » ho nang, ly nang, cao nang
ma hoi » mai hoi, xa hoi, me hoi
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ((lo nang) or (loai nang)) ((ma hoi) OR (ma hoa)). hieu van nam thuc van hanh di cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((lo nang) OR (loai nang)) ((ma hoi) OR (ma hoa)). hieu van nam thuc van hanh di cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((lo nang) or (loai nang)) ((ma hoi) OR (ma hoa)). hieu van nam thuc van hanh di cua viet".
• Adding a wildcard symbol may retrieve word variants: tu sach ((lo nang) or (loai nang)) ((ma hoi) OR (ma hoa)). hieu van nam thuc van hanh di cua viet*.