This is the 5550th most frequent Russian word.
польскими
"Polish" (adjective, instrumental plural form).
In this context, 'польскими' modifies 'пейзажами' to indicate that the landscapes being enjoyed are specifically of Polish origin.
Группа туристов наслаждалась польскими пейзажами во время путешествия.
A group of tourists enjoyed Polish landscapes during the journey.
Here, 'польскими' is used to describe the colleagues as being from Poland, indicating their origin or nationality.
Она обменялась мнениями с польскими коллегами на конференции.
She exchanged opinions with Polish colleagues at the conference.
The word 'польскими' in the instrumental case describes the nationality or origin of the publications used for research.