Perhaps you should try some spelling variations:
thanh vi » hanh vi, thanh va, thanh ve
thuc dan » hoc dan, thuc vat
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu le » hieu ve, hieu he, hieu ly
hoa hoi » khoa hoi, hoa hoc, hoa doi
ky dang » ky nang, ky danh
le nam » ly nam, he nam, le na
va hoi » xa hoi, va hoc, va hoa
vi va » vi van, vai va, vu va
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: tu sach ky dang ((va hoi) or (hoa hoi)). hieu le nam ((thuc dan) or (thuc hanh)) thanh vi va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang ((va hoi) OR (hoa hoi)). hieu le nam ((thuc dan) OR (thuc hanh)) thanh vi va thiet.
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang ((va hoi) or (hoa hoi)). hieu le nam ((thuc dan) or (thuc hanh)) thanh vi va thiet*.