Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
hieu van » hieu va, thien van, lieu va
dat luan » dan luan, dat quang, bai luan
dau luan » dan luan, khau luan, dau quang
danh di » danh du, xanh di, danh dien
va danh » va dinh, va dan, va hanh
sach ky » sac ky, sach y, sach kem
nang xa » nang x, lang xa, nang ma
sach ty » sach y, sach tu, sach thu
di cua » dai cua, doi cua, de cua

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: su ((sach ky) OR (sach ty)) nang xa hoi. hieu van ((dau luan) OR (dat luan)) va danh di cua viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) or (sach ty)) nang xa hoi. hieu van ((dau luan) OR (dat luan)) va danh di cua viet~".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sach ty)) nang xa hoi. hieu van ((dau luan) OR (dat luan)) va danh di cua viet*.