Perhaps you should try some spelling variations:
khoa viet » khoan viet, hoa viet, thoai viet
hieu hien » bieu hien, dieu hien, chieu chien
van khoa » van hoa, von khoa, san khoa
hanh van » thanh van, khanh van, hanh va
nang tai » hang tai, tang tai, sang tai
van hanh » van thanh, ban hanh, van anh
cac xuc » cac nuoc, chat xuc, cac cuoc
tang ma » mang may, tang van
sach ty » sach y, sach tu, sach thu
tu sach » thu sach, su sach, te sach

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 ((tang ma) or (nang tai)) hoi. hieu hien ((cac xuc) or (cam xuc)) van hanh van khoa viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((tang ma) OR (nang tai)) hoi. hieu hien ((cac xuc) OR (cam xuc)) van hanh van khoa viet.
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((tang ma) or (nang tai)) hoi. hieu hien ((cac xuc) or (cam xuc)) van hanh van khoa viet*.