WOW thank you, you really helped.

Andrew is absolutely right about specific "дом пушкина", but in general there could be some nuances. For example, "Улыбка Гагарина" means the smile exactly on Yuri Gagarin's face, which you maybe saw on Gagarin's picture from magazine. But pattern like "гагаринская улыбка" often means an allusion on some famous or notable person/thing/act et cetera. For example, "Джон улыбнулся знаменитой гагаринской улыбкой" insinuate that Yuri Gagarin had very recognizable smile, as a difference, and John just have used the same type of smile. The specific example will be the difference between "ружье Чехова" и "чеховское ружье"

дом пушкина - Pushkin's house пушкинский дом - The Pushkin House both mean "the house that belongs to Pushkin" in russian and in english. so there is no difference by meaning : ) why does the english language (russian or any other) have two expressions for one meaning? I don't know : ) -- гагаринская улыбка - The Gagarin smile улыбка гагарина - Gagarin's smile

дом пушкина - Pushkin's house пушкинский дом - The Pushkin House both mean "the house that belongs to Pushkin" in russian and in english. so there is no difference by meaning : ) why does the english language (russian or any other) have two expressions for one meaning? I don't know : ) -- гагаринская улыбка - The Gagarin smile улыбка гагарина - Gagarin's smile