(しんこう)  :a full-scale invasion.
(しんにゅう) In war, it means an incursion; a small raid, not an all-out invasion. More usually it means to trespass or intrude. Can also be used for an advance team of like marines or Special Ops and shit:unlike 侵略、 進入 is more secret-style, like a SWAT team entering the building where the hostages are being held.   $$$
(しんりゃく) Is a regular invasion, by troops. How is this different from 侵攻???