grant the right to select only certain rows?

If I have a table students:

name grade_level
Joe 1
Kim 1
Lisa 2
Mike 2

And I have two database users, mary_smith and tom_white. If Mary Smith
is the 1st grade teacher, is there any way to grant her access to only
select rows where grade_level=1? I think GRANT only works as a
table-wide permission, but a co-worker thinks he has seen similar
behavior in Oracle, like
"GRANT SELECT AS SELECT * FROM STUDENTS WHERE grade_level = 1
ON students FOR USER mary_smith" (Rough approximation of the type of
query I am looking for).

Thanks,
Fran