Perhaps you should try some spelling variations:
luan phan » luan van, luan hoan
hieu luan » hieu luat, hieu quan, tieu luan
duc manh » suc manh, duc anh, duc minh
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
duc van » duc va, duc tan, duc phan
su viet » so viet
x hoi » xa hoi, o hoi, x ho
vi su » va su, ve su, ki su

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 ty nang x hoi. hieu luan phan ((duc van) OR (duc manh)) hanh vi su viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang x hoi. hieu luan phan ((duc van) OR (duc manh)) hanh vi su viet".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang x hoi. hieu luan phan ((duc van) OR (duc manh)) hanh vi su viet*.