Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
thanh vai » thanh hai, thanh van, thanh oai
cua viet » ca viet, hoa viet, cua vat
hieu van » hieu va, thien van, lieu va
dua ban » dia ban, cua ban, qua ban
sach ky » sac ky, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
nam dua » nam da, nam cua, nam mua

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 y)) nang xa hoi. hieu van nam dua ban ((thanh vai) or (thanh tai)) cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sach y)) nang xa hoi. hieu van nam dua ban ((thanh vai) OR (thanh tai)) cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) OR (sach y)) nang xa hoi. hieu van nam dua ban ((thanh vai) or (thanh tai)) cua viet".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) OR (sach y)) nang xa hoi. hieu van nam dua ban ((thanh vai) or (thanh tai)) cua viet*.