Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
thuc day » thuc dan, thuc vat
cua viet » ca viet, hoa viet, cua vat
hieu van » hieu va, thien van, lieu va
hanh va » hang va, hanh vi
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
thuc va » thuc vat, thuc dan
dang xa » dang xay, lang xa, dang ha
ky dang » ky nang, ky danh

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 dang xa hoi. hieu van nam ((thuc va) or (thuc day)) hanh va ((cua viet) or (va triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky dang xa hoi. hieu van nam ((thuc va) OR (thuc day)) hanh va ((cua viet) OR (va triet)).
• Adding a wildcard symbol may retrieve word variants: su sach ky dang xa hoi. hieu van nam ((thuc va) or (thuc day)) hanh va ((cua viet) or (va triet))*.