(Note: 东 and 闻 are simplified Chinese characters for 東 and 聞.)
It's an imitation of the previous Gensokyo Chronicles books' titles (東方求聞史紀 and 東方求聞口授) . In other words, they're actually overstepping the boundary by making a fan work with a title too similar to canon. If they're in Japan, they'd get reprimanded for that.
東方求聞史紀 (PMiSS) means "Eastern Histories as Heard by Akyuu".
東方求聞口授 (SoPM) means "Eastern Oral Teachings as Heard by Akyuu".
The part they swapped in, 寻昔 means "searching for the past".
The most difficult to understand part of the original titles is 求聞. There are multiple ways of understanding this phrase*, but given the context, it can only mean "heard by Akyuu".
* It is also a reference to Akyuu's super-memory ability: 求聞持 "to retain what is heard", which originates from a type of Vajrayana Buddhist mantra 求聞持法 that helps with learning and memorization.
However, the creators of this doujinshi don't seem to know what the original titles mean, so their imitation title doesn't make very good sense.