> For the complete documentation index, see [llms.txt](https://doc.duaer.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://doc.duaer.com/getting-started/preprints.md).

# Search preprints in Duaer

In Duaer, search bioRxiv and medRxiv preprints with Duaer Data (Europe PMC). One successful search uses 1 credit. This page includes the full English call skill.
## What you get

Preprints in the Duaer data market searches bioRxiv and medRxiv via Europe PMC. One successful search uses 1 credit.

Add the node from the [Duaer Data category](/getting-started/duaer-data.md) (Preprints), or copy the skill on the [data market](/getting-started/data-market.md). For published papers, refer to [Papers](/getting-started/papers.md).

## Search on the canvas

1. Open the node creator, select Duaer Data, then Preprints.
2. Words alone is enough (a new node starts with insulin). Title, Author, DOI, Server, and Year From/To are optional.
3. Limit defaults to 10, max 20. Select Execute step.

A successful search uses 1 credit. Production deliverables land in the [data pool](/getting-started/data-pool.md).

## Call the API

- GET https://api.duaer.com/v1/data/preprints?...
- Authorization: Bearer <Duaer key>
- Fields combine; at least one search field is required (not Server alone).

For keys, refer to [Authentication for the Duaer public API](/api/authentication.md). Below is the same English call skill as Copy skill.

## Call skill

Same text as Copy skill on the Duaer data market. Keep it English.

```
---
name: duaer-preprints
description: >-
  Search bioRxiv and medRxiv preprints through Duaer (Europe PMC).
  One successful search uses 1 Duaer credit.
---

# Duaer preprints

Search bioRxiv and medRxiv preprints through Duaer with a Duaer key.

## Call

`GET https://api.duaer.com/v1/data/preprints?q=insulin&limit=10`

Header: `Authorization: Bearer <Duaer key>`

Use an account key or a model API key.

At least one search field is required (not `server` alone). Fields combine.

- `q` — words in the title or abstract.
- `title` — optional. Words in the title.
- `author` — optional. Author name.
- `doi` — optional. Digital object identifier.
- `server` — optional. `bioRxiv` or `medRxiv`. Omit for both.
- `yearFrom` — optional. First publication year (1000–2100).
- `yearTo` — optional. Last publication year (1000–2100).
- `limit` — optional. From 1 to 20. Default 10.

## Result

Each item has `source`, `title`, `url`, `summary`, `preprintId`, `doi`, `server`, `authors`, `published`, and `year`.

## Credits

One successful search uses 1 credit.
An empty search, a failed search, a compound that matches nothing, or no remaining credits uses 0.
No remaining credits returns 402 and does not search.
A missing key returns 401.

```
## Questions

### How do Duaer preprints differ from papers?

Duaer Preprints searches bioRxiv and medRxiv. Duaer Papers searches published works (OpenAlex).

## Related

- [Search papers in Duaer](https://doc.duaer.com/getting-started/papers.md)
- [Search genes in Duaer](https://doc.duaer.com/getting-started/genes.md)
- [Use the Duaer data market](https://doc.duaer.com/getting-started/data-market.md)