Perhaps you should try some spelling variations:
toan tai » toan tap, doanh tai, toan ban
van chat » cao chat
van cham » van tham, va cham, van pham
va toan » van toan, bai toan, tap toan
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
xuc va » duc va, tuc va, luc va
tai va » thai va, mai va, tri va
thiet » thieu

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 ((nang xa) OR (nang ma)) hoi. hieu ((van cham) OR (van chat)) xuc va toan tai va thiet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((nang xa) OR (nang ma)) hoi. hieu ((van cham) or (van chat)) xuc va toan tai va thiet~".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang xa) OR (nang ma)) hoi. hieu ((van cham) or (van chat)) xuc va toan tai va thiet*.