For mechanics major, I recommend two books: Course of Theoretical Mechanics, Third Edition, Zhou, Higher Education Press. This is a classic textbook of China's theoretical mechanics. I'm in the physics basic class of the physics department of Shandong University, and we use this book in our theoretical mechanics class. There is Malcef's Selected Translation of Russian Mathematics Textbooks Third Edition-Theoretical Mechanics, translated by Li Junfeng and published by Higher Education Press. This book is more in-depth and more suitable for students majoring in mechanics. As a way to improve myself, I have been reading this book recently. I hope you can learn a lot from the books you want!