Perhaps you should try some spelling variations:
thanh vai » thanh van, thanh tai, thanh oai
thanh hai » thanh phan, thanh hoa, thanh san
hieu van » hieu va, thien van, lieu va
su triet » su viet, su tien, ve triet
sach ky » sac ky, sach ty, sach kem
nang ma » tang ma, sang ma, nang cao
ma hoi » mai hoi, xa hoi, ma hoa

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) OR (sach y)) nang ma hoi. hieu van nam cua ban ((thanh vai) or (thanh hai)) su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach y)) nang ma hoi. hieu van nam cua ban ((thanh vai) OR (thanh hai)) su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) OR (sach y)) nang ma hoi. hieu van nam cua ban ((thanh vai) or (thanh hai)) su triet".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) OR (sach y)) nang ma hoi. hieu van nam cua ban ((thanh vai) or (thanh hai)) su triet*.