Is it permissible to obtain academic books from the internet to meet an urgent need for them when it is difficult to go to the library, and does searching in the library represent a restriction or is it an obligation?

If obtaining books or research papers online is authorized by their owners, then there is no problem with that. However, if they are obtained without authorization, then it is not permissible to infringe upon the rights of their owners, even though some scholars have stated that it is permissible to benefit from them for personal, non-commercial purposes.