Perhaps you should try some spelling variations:
thuc van » thuc vat, thuc dan, thuc va
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
ky dang » ky nang, ky danh
va viet » hoa viet, san viet, mai viet
me hoi » le hoi
te nam » tu nam, he nam, tw nam
vi va » vi van, vai va, vu va

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