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Semantic Scholar
✓ verifiedFree
Free AI-powered academic search engine indexing 236M+ papers, for researchers wanting semantic literature discovery and an augmented reader.
7.9M visits/mo13K saves
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Astra AI
✓ verifiedFreemium
AI tutor for school and university subjects with step-by-step help, exam prep, oral/mock exams and flashcards.
4.4M visits/mo1.7K saves
Pricing
No public pricing
No public pricing
No public pricing
Free trial available
Core features
- ✦AI-powered semantic search across 236M+ papers
- ✦Semantic Reader for augmented, contextual paper reading
- ✦Free public API for paper search and metadata
- ✦Author and topic discovery
- ✦Citation graph exploration
- ✦Beta program for new features
- ✦Video lessons
- ✦Revision notes
- ✦Quizzes
- ✦Flashcards
- ✦Exam-style questions
- ✦Past papers
- ✦Step-by-step subject explanations
- ✦Photo-based math problem solving
- ✦Oral and mock exam practice with grading
- ✦Personalized study plans
- ✦Flashcards from uploaded notes
- ✦Coverage of many subjects, user-created subjects
Use cases
- →Researchers searching scientific literature across disciplines
- →Developers building applications on top of scholarly data via the API
- →Students exploring citation networks for a topic
- →Librarians and academics needing free literature discovery tools
- →Preparing for Maths and Science exams at KS3, GCSE, and A-Level.
- →Prepare for school or university exams
- →Get help understanding tough concepts
- →Practice oral exams out loud
- →Study from your own notes
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