Perhaps you should try some spelling variations:
thanh hai » thanh phan, thanh hoa, thanh san
su triet » su viet, su tien, ve triet
hieu van » hieu va, thien van, lieu va
sach ty » sach y, sach tu, sach thu
nang ma » tang ma, sang ma, nang cao
sach ky » sac ky, sach y, sach kem
nam duc » nam duoc, pham duc, nam thuc
duc gia » quoc gia
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: su ((sach ky) OR (sach ty)) nang ma hoi. hieu van nam duc gia ((thanh hai) or (tinh toan)) su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sach ty)) nang ma hoi. hieu van nam duc gia ((thanh hai) OR (tinh toan)) su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) OR (sach ty)) nang ma hoi. hieu van nam duc gia ((thanh hai) or (tinh toan)) su triet".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) OR (sach ty)) nang ma hoi. hieu van nam duc gia ((thanh hai) or (tinh toan)) su triet*.