This is the original text in the source you want to use:
A central theme of Tan’s stories is the conflict faced by Chinese Americans who find themselves alienated both from their American milieu and from their Chinese parents and heritage. (Stein 2001, 2280).
Below the student is plagiarizing. The reader has no way of knowing that the idea, which has been paraphrased (rewritten) from the original text, comes from the passage above:
Amy Tan’s stories are often about Chinese American characters who experience conflict in dealing with their parents and their Chinese heritage and in relating to the American society in which they live.
If you do not make clear in the text itself where you are using an author's ideas, you are committing plagiarism--even if you credit the author in a bibliography or reference list