How to Use Ocean of Papers: Complete Tutorial for Search, PDFs, Citation Maps and Library (2026)

Quick answer

Ocean of Papers is a free academic search engine. Type a topic or paste a DOI, filter the results, click PDF to open a legal open-access copy, and export citations in BibTeX, RIS, CSV or APA/MLA style. Click Citation map on any result to see related papers. A free account adds a synced library with projects, notes, tags, Import and Discover. Pro only adds unlimited maps.

Ocean of Papers in One Minute

Ocean of Papers is a free tool for finding, reading and organizing research papers. It searches six open scholarly databases at once (OpenAlex, PubMed, arXiv, bioRxiv, medRxiv and Europe PMC, 250M+ papers), shows a PDF button when a legal free copy exists, and lets you turn any paper into an interactive citation map.

Updated October 2026.

This tutorial walks through every feature in the order most students and researchers use them: search → filter → open PDFs → cite and export → map → save to a library → import and discover. If you want the short background on what the tool is and where its data comes from, read what is Ocean of Papers first.

Jump to: Search · Filters · DOI · PDFs · Cite and export · Table and Swipe · Citation map · Library · Import and Discover · Free vs Pro · Is it safe? · FAQ

1. Search — Topic, keywords or a DOI across 6 databases
2. Filter and sort — Year, citations, journal, field, source, PDF only
3. Open the PDF — Legal open-access copies only
4. Build a citation map — See earlier, later and similar papers
5. Save and export — Library projects, notes, tags; BibTeX, RIS, CSV

Step 1: Search Across Six Databases

Go to the home page and type your topic into the search bar. You do not need an account.

• Be specific. "screen time sleep quality adolescents" gives better results than "sleep".
• Use quotation marks for exact phrases, for example "machine learning".
• Pick your sources. Use the source toggles to search all six databases or only some: PubMed and Europe PMC for medicine and life sciences, arXiv for computer science, physics and maths, bioRxiv and medRxiv for recent preprints in biology and health, and OpenAlex for every field.

Each result shows the title, authors, year, journal or source, citation count and an abstract snippet. The results header shows how many results came from each database. Click a title to see the full abstract and details.

Not sure how this compares with other search engines? See our list of free academic search engines and Google Scholar alternatives.

Step 2: Filter and Sort Your Results

Open the filters (the sidebar on desktop, the Filters drawer on mobile) to narrow a long list:

• Sort: Relevance, Most Cited (good for classic, foundational papers) or Most Recent (good for the latest work).
• Year: set a from and to year, for example the last five years for a review of related literature.
• Min Citations: hide papers with very few citations.
• Journals and Fields of study: search for and select specific journals or fields.
• PDF only: show only results with a free legal PDF.

Active filters appear as chips above the results. Click a chip to remove that filter. If a search returns nothing, try turning off PDF only or widening the year range.

Step 3: Paste a DOI to Find One Exact Paper

If you already know the paper you need (from a reference list, a syllabus or a teacher's slide), paste its DOI into the search bar, for example `10.1186/s12909-024-05889-y`. Ocean of Papers finds that exact paper, so you can open its PDF if one is free, copy a citation, or start a citation map from it.

You can paste a bare DOI or a full https://doi.org/ link. For more on this, read how to download a research paper by DOI.

Step 4: Open Free PDFs (Legally)

When a free, legal copy of a paper exists, the result shows a PDF button. Click it to open the full text. These links come from Unpaywall, PubMed Central, arXiv, bioRxiv and medRxiv: open-access journals, author-deposited copies in repositories, and preprint servers.

If there is no PDF button, the paper is probably only available by subscription. Click the title to go to the publisher or DOI page, check if your school library has access, look for a preprint version, or email the author. Our guide on how to read paywalled papers legally lists every legal option, and how to download research papers for free covers more routes.

Step 5: Cite and Export

Cite one paper. Click Cite on a result to copy a formatted citation in APA, MLA, Chicago, Harvard, Vancouver or BibTeX. Always double-check capitalization and italics against your school's style guide; automatic citations are a starting point, not a final check.

Export many papers. Use the export menu to download results or your saved papers as BibTeX, RIS, CSV or plain text. BibTeX and RIS open in Zotero, Mendeley, EndNote and LaTeX; CSV opens in Excel or Google Sheets, which is handy for a literature matrix.

Exports are free and unlimited.

Step 6: Switch to Table or Swipe View

The default list view is best for reading. Two other views help when you have many results:

• Table view shows results in rows and columns, so you can scan titles, years and citation counts quickly and compare papers side by side.
• Swipe view shows one paper at a time as a card. Swipe right (or tap save) to keep it, left to skip. It is the fastest way to triage a long list into a short reading list. See the full swipe mode guide.

Switch views from the view selector at the top of the results.

Step 7: Build a Citation Map

A citation map shows how papers connect. Click Citation map on any search result (or on a paper found by DOI). Ocean of Papers builds a map of about 30 related papers around it. You can choose 15, 30 or 50 papers.

Three modes:

• Similar: papers most closely related to your starting paper.
• Prior works: the papers it builds on (its references and their neighbours).
• Derivative works: later papers that cite it.

Two layouts:

• Graph: a network. Bigger circles are more cited; darker circles are newer.
• Timeline: papers placed by year (across) and citation count (up, on a log scale), so you can see how a topic grew.

Why are two papers linked? Links can mean a direct citation, shared references (bibliographic coupling), co-citation (cited together by other papers) or a shared author. Click a link to see the reason.

Going further:

• Click any paper to open the Explore panel: Similar work, Earlier work, Later work and These authors, each with Add to map.
• Use Add as seed, or select up to 10 papers, to map several papers together.
• The side list has Prior works and Derivative works tabs for the whole map: the classics most papers in your map cite, and newer papers that cite many of them.
• Use back and forward to move through your map history.
• Export the map as PNG (for slides), or the papers as BibTeX, RIS or CSV. Share a link with a classmate or adviser.

Learn the ideas behind the map in our citation network explainer, and see how it compares with other tools on the literature mapping tool page.

1. Search or paste a DOI — Find one strong paper on your topic
2. Click Citation map — About 30 papers (choose 15, 30 or 50)
3. Switch mode — Similar, Prior works or Derivative works
4. Try Timeline — Year × citations to see how the field grew
5. Explore and add — Add to map, Add as seed, then export or share

Step 8: Save Papers to Your Library

Searching, PDFs, exports and citation maps work without an account. To save papers, create a free account. Your library is stored in your account (not your browser), so it syncs across your laptop and phone.

• Projects: group papers by thesis chapter, assignment or topic.
• Notes: write a summary or key quote for each paper, which saves time when you write your review of related literature.
• Tags: label papers (for example "method", "theory", "local study") and filter by tag.
• Export a project as BibTeX, RIS, CSV or text when you are ready to write.

For a full writing workflow from saved papers, read how to write a literature review.

Step 9: Import Your Papers and Use Discover

Import. In your library, click Import to bring in papers you already have. You can import from Zotero (a one-time import), a BibTeX or RIS file (exported from Mendeley, EndNote or another tool), or a pasted list of DOIs. Imported papers go into the project you choose.

Discover. Open a project and click Discover. Ocean of Papers looks at the papers in that project and ranks papers it seems to be missing, each with a reason: cited by N of your papers (foundational work), cites N of your papers (follow-ups), similar to papers you have, or by the same authors. Add any suggestion to the project in one click.

Discover is useful near the end of a literature review, to check you have not missed an important study your sources keep citing.

All Features at a Glance

Here is everything Ocean of Papers does today, and what you need to use it.

Is Ocean of Papers Free? Free vs Pro

Yes. Search, PDFs, citations, exports, the library, Import and Discover are free with no limits. The free plan includes 5 new citation maps per month. Switching modes, changing the layout or expanding an existing map does not count as a new map.

Pro removes the map limit (unlimited citation maps). It costs $9/month or $79/year, or ₹299/month or ₹2,499/year in India. Everything else is the same as free. See the pricing page for current details.

Is Ocean of Papers Legal, Safe and Legit?

Legal: Yes. Ocean of Papers only searches open scholarly databases and only links to PDFs that are legally free: open-access journal articles, author copies in repositories such as PubMed Central, and preprints on arXiv, bioRxiv and medRxiv. It does not host pirated copies, does not bypass paywalls, and does not link to piracy sites. If a paper is paywalled, it shows you the publisher's page instead.

Safe: You can search, open PDFs, export and build citation maps without creating an account or giving any personal details. An account (email and password) is only needed to save a library. PDFs open from the original open-access source.

Legit: The data comes from well-known public sources: OpenAlex, the US National Library of Medicine's PubMed, Europe PMC, arXiv, bioRxiv and medRxiv. You can check any paper by clicking through to its DOI or source page.

As with any search tool, it is still your job to judge the quality of what you read: check whether a paper is peer-reviewed or a preprint, and look at the journal and methods.

What Ocean of Papers Does Not Do (Yet)

To be clear about limits, these features are not available today:

• Email alerts for new papers on a topic or from an author.
• Two-way Zotero sync. Zotero import is one-time; changes are not synced back.
• Shared or collaborative projects. Libraries are personal. To share, send a map link or an exported BibTeX/RIS file.
• Full-text search inside PDFs. Search covers titles, abstracts and metadata; Google Scholar is stronger here.
• Paywalled papers. If no legal free copy exists, there is no PDF button.

If you need alerts or team libraries now, other tools may fit better; see our comparisons with ResearchRabbit, Litmaps and Connected Papers, and the full list of best literature mapping tools.

Tips for Students Writing a Thesis or Research Paper

1. Start with one strong paper. Search your topic, sort by Most Cited, and pick a well-cited study close to your variables.
2. Map it. Use Prior works to find the classics for your theoretical framework and Derivative works for recent studies for your RRL.
3. Save as you go. Make a project per chapter and add a one-line note to each paper.
4. Export a CSV of your project to build a literature matrix (author, year, method, findings).
5. Run Discover before your defense to catch any major study you missed.

Ready to try it? Start searching free. For the writing side, see how to write a research paper.

FAQ

What is Ocean of Papers?

Ocean of Papers is a free academic search engine and literature mapping tool. It searches OpenAlex, PubMed, arXiv, bioRxiv, medRxiv and Europe PMC (250M+ papers) in one place, shows free legal PDFs, exports citations, and builds interactive citation maps.

How do I use Ocean of Papers?

Type a topic or paste a DOI into the search bar, filter the results, click PDF to read a free copy, click Cite or Export for references, and click Citation map to find related papers. Create a free account to save papers into projects.

Is Ocean of Papers free?

Yes. Search, PDFs, citations, exports, the library, Import and Discover are free. The free plan includes 5 new citation maps per month. Pro ($9/month or $79/year; ₹299/₹2,499 in India) adds unlimited maps.

Is Ocean of Papers safe and legit?

Yes. It uses public scholarly databases, links only to legal open-access PDFs, and does not require an account for searching or reading. An account is only needed to save a library.

Is Ocean of Papers legal?

Yes. It never bypasses paywalls or links to pirated copies. PDFs come from open-access sources such as Unpaywall, PubMed Central, arXiv, bioRxiv and medRxiv.

Do I need an account to use Ocean of Papers?

No for search, PDFs, citations, exports and citation maps. Yes (free) for saving papers to a library, using projects, notes and tags, Import and Discover.

Why doesn't every paper have a PDF button?

Because many papers are only available by subscription. Ocean of Papers shows a PDF button only when a legal free copy exists. For other papers, try your library, a preprint version or the author.

Can I import my Zotero library into Ocean of Papers?

Yes, as a one-time import. You can also import a BibTeX or RIS file or a list of DOIs. Two-way Zotero sync is not available.

Related guides

• What is Ocean of Papers?
• Free literature mapping tool (citation maps)
• Citation network: what it is and how to make one free
• How to download a research paper by DOI
• How to write a literature review (with example PDFs)

Search free research papers · Build a citation map from any search result · Browse all research guides