Perhaps you should try some spelling variations:
hieu luan » hieu luat, hieu quan, tieu luan
luan phan » luan van, luan hoan
phan duc » pham duc, phan tu, phan dau
va trien » va truyen, va thiet, va tuyen
xang ma » tang ma, nang ma, sang ma
sach ty » sach tu, sach thu, xach tay
va danh » va dinh, va dan, dia danh
va hanh » van hanh, va thanh, ban hanh
ma hoi » mai hoi, xa hoi, ma hoa
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: so ((sach ty) OR (sach y)) xang ma hoi. hieu luan phan duc ((va danh) or (va hanh)) vi va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sach ty) OR (sach y)) xang ma hoi. hieu luan phan duc ((va danh) OR (va hanh)) vi va trien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so ((sach ty) OR (sach y)) xang ma hoi. hieu luan phan duc ((va danh) or (va hanh)) vi va trien".
• Adding a wildcard symbol may retrieve word variants: so ((sach ty) OR (sach y)) xang ma hoi. hieu luan phan duc ((va danh) or (va hanh)) vi va trien*.