distinct, dramatic, fundamental, huge, important, major, marked, massive, profound, pronounced, radical, seismic, significant, substantial
There has been a major shift in the public's taste.
a significant shift in policy

discernible, perceptible
slight, subtle
gradual
abrupt, rapid, sudden
decisive, irreversible, long-term
climate, cultural, demographic, ideological, policy, population, power
paradigm (= an important change in the way sth is thought about)
Einstein's theories caused a paradigm shift in scientific thought.

be, mark, represent
These proposals represent a dramatic shift in policy.

indicate, reflect, signal
The moment signals a significant shift in attitudes to the war.

show
detect, notice, observe, see, witness
I detected a subtle shift towards/toward our point of view.

bring about, cause, drive, lead to, produce, result in
experience, undergo
The industry has undergone a fundamental shift in recent years.
The toy industry is undergoing a seismic shift as more products are manufactured overseas.

explain
one factor which may explain the president's policy shift

occur, take place
These climate shifts occurred over less than a decade.

shift between
the many shifts between verse and prose that occur in Shakespeare

shift (away) from
the shift away from direct taxation

shift in
a shift in public opinion
a shift in attitude/opinion/perspective
a shift in emphasis/mood/tone
a shift in direction/focus/policy/strategy

shift to
a sudden shift to the right in politics

shift towards/toward
a shift towards/toward part-time farming

double, long, split (esp. BrE)
I agreed to work double shifts for a few weeks.

day, early
late, swing (AmE)
graveyard (esp. AmE), night, overnight
eight-hour, ten-hour, etc.
afternoon, evening, morning, weekend

do, work
I'm doing the early shift this week.
He works the night shift.
I didn't realize that I'd have to work shifts.

be on, come on, go on
be off, come off, finish, go off
change
It was 8 a.m. and the nurses were changing shifts.
My husband changed his shifts from afternoons to nights.

begin (esp. BrE), start (esp. AmE)
end
change

work
manager, supervisor, worker
pattern, system (both BrE)
They'd altered his shift pattern twice in the past month.

change
The shift change took place at 10 p.m.

in shifts
The clinic is staffed by ten doctors who work in shifts.

on a/the shift
a decision for the chief nurse on each shift

slightly
Julie shifted her position slightly and smiled.

impatiently, nervously, restlessly, uncomfortably, uneasily
She shifted uncomfortably in her chair.

away

from
She shifted her gaze away from the group of tourists.

onto
He shifted his weight onto his left foot.

to
Her eyes shifted to his face.

shift from foot to foot
shift in your chair, shift in your seat

dramatically, markedly, radically
The emphasis has shifted markedly in recent years.

slightly
effectively
simply
We cannot simply shift the responsibility onto someone else.

gradually, slowly
quickly, rapidly
suddenly
constantly, continually
constantly shifting alliances

away
Government grants are being shifted away from the capital to the regions.

attempt to, try to
They tried to shift the blame onto the government.

tend to
begin to

(away) from
I felt the advantage had suddenly shifted away from us.

back, back and forth
Like many plays, this one shifts back and forth in time and place.

into (AmE)
to shift into second gear

out of
In recent years, manufacturing has shifted out of the US.

onto, to
His sympathies rapidly shifted to the side of the workers.

towards/toward
These changes will shift the balance more towards/toward science subjects.

Shift is used with these nouns as the subject:
attention, attitude, balance, emphasis, eye, focus, gaze, mood, scene

Shift is used with these nouns as the object:
allegiance, attention, balance, blame, bulk, burden, debate, direction, emphasis, focus, gaze, gear, grip, loyalty, perception, perspective, position, responsibility, stance, tactic, weight