Perhaps you should try some spelling variations:
va triet » va trien, ve triet, cua triet
hanh vai » hanh vi, hanh va, hanh tai
thuc dan » thuc hanh, hoc dan, thuc vat
su sach » so sach, vu sach
thuc va » thuc vat, thuc day
sach ty » sach y, sach tu, sach thu
hieu ve » hieu va, hieu van
nang ma » tang ma, sang ma, nang cao
ty nang » ky nang, ty xang, ty hang
ve nam » he nam, va nam, le nam
ma hoi » mai hoi, xa hoi, ma hoa
thiet » thieu

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 ty nang ma hoi. hieu ve nam ((thuc va) or (thuc dan)) hanh vai ((va triet) or (va thiet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang ma hoi. hieu ve nam ((thuc va) OR (thuc dan)) hanh vai ((va triet) OR (va thiet)).
• Adding a wildcard symbol may retrieve word variants: su sach ty nang ma hoi. hieu ve nam ((thuc va) or (thuc dan)) hanh vai ((va triet) or (va thiet))*.