who can help me explain the concepts of "Semantic Web", "Semantic Network", "Semantic Search", "Knowledge graph"(not Google's Knowledge Graph) and "knowledge base" and the relations among them?
Semantic Web is a set of technologies that want to make the data on the web readable and understood by machines. The domain that semantic web is the web. Therefore the URI is in the bottom of the technologies stack.
Semantic Network is a graph model to store the information. If you can model your data as a graph with node and edge, you can think it as a semantic network.
Knowledge graph is also a kind of graph model. However, it emphasis the store of all data on the level of both schema and individual. Therefore, it has no essential difference with Semantic network. Knowledge base is an instantiated storage of a domain knowledge. You can think it as a database. It has not to be a graph model, if you can store the knowledge in some way, you can call it as knowledge base.