Perhaps you should try some spelling variations:
hieu luan » hieu luat, hieu quan, tieu luan
luan phan » luan van, luan hoan
van hanh » van thanh, ban hanh, van anh
sach thu » sach thue, sach thieu, sach tham
phan duc » pham duc, phan tu, phan dau
duc van » duc va, duc tan, duc manh
sach ty » sach y, sach tu, xach tay
x hoi » xa hoi, o hoi, x ho
vi su » ve su, ki su, oi su

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ty) OR (sach thu)) nang x hoi. hieu luan phan duc van hanh ((vi su) OR (va su)) viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ty) OR (sach thu)) nang x hoi. hieu luan phan duc van hanh ((vi su) or (va su)) viet~".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ty) OR (sach thu)) nang x hoi. hieu luan phan duc van hanh ((vi su) or (va su)) viet*.