One of the best is Elicit, which is good at finding, summarizing and extracting information from academic papers. It's geared for empirical subjects like biomedicine and machine learning, and it can help you with tasks like accelerating literature reviews, finding new papers and automating systematic reviews. Elicit's higher-end features include the ability to upload your own papers for analysis and to converse with the content.
Another strong option is Semantic Scholar, a free AI-powered research service that indexes more than 219 million papers across all scientific fields. It's got tools for searching, summarizing, citing, organizing and recommending papers based on your interests. You can also set up automated email alerts and track research with its dedicated dashboard, making it a good all-purpose research assistant.
Avidnote is another general-purpose AI tool to help you get your research done. It can help you write research papers, rewrite text, generate literature reviews and proofread. With features like automatic transcription, support for multiple languages and advanced AI templates, Avidnote is a good option for academics and pros.
If you like a more structured approach, Enago Read has a number of features, including smart organization, personalized recommendations and a reading space for collaboration. It also can generate summaries and has a copilot feature to explain technical terms, so it can be a good assistant for academic researchers.