No, for 2 reasons. First, because unless they say otherwise, abilities of permanents only function while they are on the battlefield.
112.6. Abilities of an instant or sorcery spell usually function only while that object is on the stack.
Abilities of all other objects usually function only while that object is on the battlefield. The exceptions are as follows:
None of the exceptions relate to the ability in question.
Also, Slivers that are in your graveyard will not even get that ability in the first place. When a card says "All Slivers", it refers to all Sliver permanents, and a permanent is a card or token on the battlefield.
609.2. Effects apply only to permanents unless the instruction’s text states otherwise or they clearly can
apply only to objects in one or more other zones.
Example: An effect that changes all lands into creatures won’t alter land cards in players’
graveyards. But an effect that says spells cost more to cast will apply only to spells on the
stack, since a spell is always on the stack while a player is casting it.
110.1. A permanent is a card or token on the battlefield.