Perhaps you should try some spelling variations:
vat hanh » vat thanh, van hanh, va hanh
sach ty » sach y, sach tu, sach thu
nang xa » nang x, lang xa, nang ma
hanh va » hang va, hanh vi
su tien » su kien, su hien, tu tieng
sai ky » sac ky
va cau » van cau, va cac, va cao
va dau » va dao

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) or (sai ky)) nang xa hoi. hieu ((va cau) OR (va dau)) thuc vat hanh va su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ty) OR (sai ky)) nang xa hoi. hieu ((va cau) OR (va dau)) thuc vat hanh va su tien*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ty) or (sai ky)) nang xa hoi. hieu ((va cau) OR (va dau)) thuc vat hanh va su tien*".