---
name: "xpay-paper-search-search-crossref"
description: "Search academic papers from CrossRef database.
    
    CrossRef is a scholarly infrastructure organization that provides 
    persistent identifiers (DOIs) for scholarly content and metadata.
    It's one of the largest citation databases covering millions of 
    academic papers, journals, books, and other scholarly content.

    Args:
        query: Search query string (e.g., 'machine learning', 'climate change').
        max_results: Maximum number of papers to return (default: 10, max: 1000).
        **kwargs: Additional search parameters:
            - filter: CrossRef filter string (e.g., 'has-full-text:true,from-pub-date:2020')
            - sort: Sort field ('relevance', 'published', 'updated', 'deposited', etc.)
            - order: Sort order ('asc' or 'desc')
    Returns:
        List of paper metadata in dictionary format.
        
    Examples:
        # Basic search
        search_crossref(\"deep learning\", 20)
        
        # Search with filters
        search_crossref(\"climate change\", 10, filter=\"from-pub-date:2020,has-full-text:true\")
        
        # Search sorted by publication date
        search_crossref(\"neural networks\", 15, sort=\"published\", order=\"desc\")
    "
version: "1.0.0"
price: "$0.01/call"
provider: "Paper Search"
---

# Search Crossref

Search academic papers from CrossRef database.
    
    CrossRef is a scholarly infrastructure organization that provides 
    persistent identifiers (DOIs) for scholarly content and metadata.
    It's one of the largest citation databases covering millions of 
    academic papers, journals, books, and other scholarly content.

    Args:
        query: Search query string (e.g., 'machine learning', 'climate change').
        max_results: Maximum number of papers to return (default: 10, max: 1000).
        **kwargs: Additional search parameters:
            - filter: CrossRef filter string (e.g., 'has-full-text:true,from-pub-date:2020')
            - sort: Sort field ('relevance', 'published', 'updated', 'deposited', etc.)
            - order: Sort order ('asc' or 'desc')
    Returns:
        List of paper metadata in dictionary format.
        
    Examples:
        # Basic search
        search_crossref("deep learning", 20)
        
        # Search with filters
        search_crossref("climate change", 10, filter="from-pub-date:2020,has-full-text:true")
        
        # Search sorted by publication date
        search_crossref("neural networks", 15, sort="published", order="desc")
    

**Provider:** Paper Search
**Price:** $0.01/call
**Pricing model:** Flat rate per call

## When to Use

Use this tool when you need to search academic papers from crossref database.
    
    crossref is a scholarly infrastructure organization that provides 
    persistent identifiers (dois) for scholarly content and metadata.
    it's one of the largest citation databases covering millions of 
    academic papers, journals, books, and other scholarly content.

    args:
        query: search query string (e.g., 'machine learning', 'climate change').
        max_results: maximum number of papers to return (default: 10, max: 1000).
        **kwargs: additional search parameters:
            - filter: crossref filter string (e.g., 'has-full-text:true,from-pub-date:2020')
            - sort: sort field ('relevance', 'published', 'updated', 'deposited', etc.)
            - order: sort order ('asc' or 'desc')
    returns:
        list of paper metadata in dictionary format.
        
    examples:
        # basic search
        search_crossref("deep learning", 20)
        
        # search with filters
        search_crossref("climate change", 10, filter="from-pub-date:2020,has-full-text:true")
        
        # search sorted by publication date
        search_crossref("neural networks", 15, sort="published", order="desc")
    . This is part of the Paper Search provider on xpay✦.

## MCP Connection

Connect to xpay✦ to access this tool (and 24+ others):

```json
{
  "mcpServers": {
    "xpay": {
      "url": "https://mcp.xpay.sh/mcp?key=YOUR_API_KEY"
    }
  }
}
```

For Claude Code:
```bash
claude mcp add --transport http xpay "https://mcp.xpay.sh/mcp?key=YOUR_API_KEY"
```

## How to Execute

Use the xpay✦ meta-tools to run this tool:

1. **`xpay_details`** — Get full input schema: `xpay_details("paper-search/search_crossref")`
2. **`xpay_run`** — Execute: `xpay_run("paper-search/search_crossref", { ...inputs })`

## Input Parameters

| Parameter | Type | Required | Description |
|-----------|------|----------|-------------|
| `kwargs` | string | Yes |  |
| `max_results` | integer | No |  |
| `query` | string | Yes |  |

## Pricing

- **Cost:** $0.01/call
- **Balance check:** Use `xpay_balance` to check remaining credits
- Get your API key at [xpay.tools](https://xpay.tools/account/settings/api-keys/) — $5 free credits included

## Related Skills

- [Paper Search (all tools)](https://xpay.tools/skills/paper-search/SKILL.md) — 25 tools
- [Search](https://xpay.tools/skills/paper-search/search/SKILL.md) — $0.01/call
- [Fetch](https://xpay.tools/skills/paper-search/fetch/SKILL.md) — $0.01/call
- [Search Arxiv](https://xpay.tools/skills/paper-search/search-arxiv/SKILL.md) — $0.01/call
- [Search Pubmed](https://xpay.tools/skills/paper-search/search-pubmed/SKILL.md) — $0.01/call
- [Search Biorxiv](https://xpay.tools/skills/paper-search/search-biorxiv/SKILL.md) — $0.01/call

## Links

- Tool page: https://xpay.tools/paper-search/search-crossref/
- Provider: https://xpay.tools/paper-search/
- All tools: https://xpay.tools/explore