Search scientific literature and read full-text content from peer-reviewed papers.
Use `dois` (preferred) or `titles` with targeted `term` queries to extract full-text passages from specific papers. Each call returns up to 5 relevant excerpts (~500 chars each) — vary search terms across calls to read through a paper section by section.
**IMPORTANT — keep `limit` small.** Use `limit: 10-50` with `offset` for pagination. Large limits with full citations and excerpts produce very large payloads that consume significant LLM context.
**Calling with no parameters browses the corpus** (210M+ papers, relevance-sorted). This is allowed for broad exploration but rarely what you want — pass `term`, `dois`, `titles`, or other filters for targeted results.
**What This Tool Returns:**
- Paper metadata: title, authors (first 3), abstract, DOI, journal, year, volume, issue, page
- `fulltextExcerpts`: up to 5 passages (~500 chars) from the paper matching your query (OA only)
- `access`: resolved access link with source, type (open/institutional/purchase), content type, and pricing
- `citations`: Smart Citation statements — actual quoted text from citing papers, classified as supporting/contrasting/mentioning/unclassified (unclassified = statement present but classifier hasn't assigned a type)
- `tally`: citation metrics (total, supporting, contrasting, mentioning, citing publications)
- `editorialNotices`: editorial notices (retraction, correction, concern, erratum), each with status, noticeDoi, date
- `isOa`, `oaStatus`, `license`: open access information
**Fetching Paper Metadata (no search term needed):**
Pass `dois` or `titles` WITHOUT a `term` to retrieve metadata for specific papers.
Example: `dois: ["10.1038/s41586-020-2012-7"]`
**Full-Text Excerpts:**
For OA papers, `fulltextExcerpts` contains passages matching your query. If empty, the full text is not indexed or terms didn't match — use the `access` field for the best link to the PDF or full text.
**Smart Citations ARE Full-Text Evidence:**
- `snippet`: exact sentence/paragraph from the citing paper's full text
- `type`: classification (supporting, contrasting, mentioning, unclassified)
- `section`: paper section (Introduction, Methods, Results, Discussion)
- `sourceDoi`: paper containing this snippet; `targetDoi`: paper being cited
**Search Capabilities:**
- Boolean operators: AND, OR, NOT
- Phrase search: "exact phrase"
- Proximity: "term1 term2"~5
- Field filters: title, abstract, author, journal, year, affiliation
- Citation filters: supporting_from/to, contrasting_from/to, mentioning_from/to
- Editorial filters: has_retraction, has_concern, has_correction, has_erratum
**Parameters:**
- `term`: cross-field search query (optional when `dois`/`titles` provided)
- `dois`: array of DOIs to filter to specific papers
- `titles`: array of titles to filter (use when DOIs unavailable)
- `limit`: max results (default: 10, max: 1000)
- `offset`: pagination offset
- Plus 20+ filter parameters (see schema)
**Response Format:**
```json
{
"hits": [{
"doi": "10.1234/example",
"title": "Paper Title",
"authors": [{"authorName": "Jane Smith"}],
"abstract": "Full abstract text...",
"year": 2023,
"journal": "Nature",
"tally": {"supporting": 32, "contrasting": 8, "mentioning": 5},
"fulltextExcerpts": ["Relevant passage..."],
"access": {"url": "https://...", "accessType": "open", "contentType": "pdf"},
"citations": [{"snippet": "These findings...", "type": "supporting", "section": "Results"}],
"editorialNotices": [{"status": "retracted", "noticeDoi": "10.1234/notice", "date": "2021"}]
}]
}
```