# BASE as a Gemini Notebook source > Academic search engine indexing hundreds of millions of documents. Filter to open access to surface PDFs you can actually upload. _Markdown version of https://gemini-notebook-hub.online/sources/base — for AI and LLM crawlers. Content is identical to the web page._ --- - Site: [base-search.net](https://www.base-search.net) - Category: Academic papers - Access: free Academic search engine indexing hundreds of millions of documents. Filter to open access to surface PDFs you can actually upload. Run by Bielefeld University Library, BASE indexes several hundred million documents from repositories worldwide, including theses and reports that a general academic search often misses. Filtering to open access narrows results to things you can legally upload as PDFs. Because it aggregates so many different repositories, quality and peer-review status vary a lot between results, so check the source before trusting a claim from it. ## Import into Gemini Notebook 1. Copy the link: https://www.base-search.net 2. In your notebook, click Add source → Website. 3. Paste the link and confirm — several links can be pasted at once, one per line. **Tip:** Gemini Notebook reads the text of the page you give it. Paste pages that carry the full text (an arXiv abs page, a PubMed Central article) — a paywalled landing page imports as just an abstract. ## More academic papers sources - [Google Scholar](https://gemini-notebook-hub.online/sources/google-scholar.md) — The widest net for finding papers across every field; follow its links to a full-text version before importing. - [arXiv](https://gemini-notebook-hub.online/sources/arxiv.md) — Preprints for AI, CS, math and physics. Paste the abs page URL as a Website source — figures survive that route better than an uploaded PDF. - [Semantic Scholar](https://gemini-notebook-hub.online/sources/semantic-scholar.md) — AI-assisted paper discovery with citation graphs — good for building the reading list before you build the notebook. - [PubMed Central](https://gemini-notebook-hub.online/sources/pubmed-central.md) — Free full-text biomedical papers — unlike PubMed proper, articles here import complete, not as abstracts. - [SSRN](https://gemini-notebook-hub.online/sources/ssrn.md) — Working papers in economics, law, finance and the social sciences, most downloadable as full-text PDFs. - [Academia.edu](https://gemini-notebook-hub.online/sources/academia-edu.md) — Researcher-uploaded papers across every discipline. Useful for finding PDFs that are paywalled elsewhere; an account is needed for downloads. - [Connected Papers](https://gemini-notebook-hub.online/sources/connected-papers.md) — Builds a visual graph of papers related to one you pick. Good for finding what to read next — then add the actual PDFs or abstract pages to Gemini Notebook. - [Consensus](https://gemini-notebook-hub.online/sources/consensus.md) — AI search that answers questions with citations to peer-reviewed studies. Use it to shortlist papers, then import the papers themselves as sources. - [CORE](https://gemini-notebook-hub.online/sources/core.md) — Aggregator of open-access papers from repositories worldwide — a good first stop for finding a free PDF of a paywalled article. - [Crossref Metadata Search](https://gemini-notebook-hub.online/sources/crossref-metadata-search.md) — DOI lookup and metadata for 150M+ scholarly works. Use it to trace citations and find the canonical publisher page before adding a paper as a source. - [Dimensions](https://gemini-notebook-hub.online/sources/dimensions.md) — Research graph linking papers to the grants, patents, clinical trials and policy documents that cite them. Free tier covers basic publication search. - [Directory of Open Access Journals](https://gemini-notebook-hub.online/sources/directory-of-open-access-journals.md) — Index of vetted open-access journals in every field. Useful for confirming a journal is legitimate and finding free full-text versions to import. - [EBSCO Open Dissertations](https://gemini-notebook-hub.online/sources/ebsco-open-dissertations.md) — Free index of theses and dissertations from universities worldwide. Records link to institutional repositories where full-text PDFs are often available. - [Elicit](https://gemini-notebook-hub.online/sources/elicit.md) — AI assistant that searches papers and extracts findings into tables. Use it to shortlist studies, then import the underlying papers into Gemini Notebook. - [NDLTD](https://gemini-notebook-hub.online/sources/ndltd.md) — Union catalog for electronic theses and dissertations worldwide. Dissertations run long — import specific chapters as PDFs rather than whole volumes. - [OpenAlex](https://gemini-notebook-hub.online/sources/openalex.md) — Free index of hundreds of millions of scholarly works with citation links. Good for mapping a literature before deciding which papers to import. - [Oxford Bibliographies Online](https://gemini-notebook-hub.online/sources/oxford-bibliographies-online.md) — Scholar-written reading guides that map the key literature on a topic. Use an entry to decide which papers to pull into your notebook before you start importing. - [ProQuest Dissertations & Theses Global (PQDT)](https://gemini-notebook-hub.online/sources/proquest-dissertations-and-theses-global-pqdt.md) — The biggest collection of dissertations worldwide, with full text for most recent work. Needs institutional access; theses make dense, citable sources. - [RefSeek](https://gemini-notebook-hub.online/sources/refseek.md) — Stripped-down academic search that filters out commercial results. Useful for surfacing reference pages and documents to add as notebook sources. - [ResearchGate](https://gemini-notebook-hub.online/sources/researchgate.md) — Social network where authors upload their own papers. Often has a free full-text copy when the journal version is paywalled — check here before giving up. - [SciELO](https://gemini-notebook-hub.online/sources/scielo.md) — Open-access journal network centered on Latin America, with Spanish and Portuguese full text. Good for research the big English-language indexes miss. - [Scopus](https://gemini-notebook-hub.online/sources/scopus.md) — Elsevier's citation index for tracking who cites what across peer-reviewed literature. Use it to build a reading list, then import the papers themselves. - [The Lens – Scholarly Works](https://gemini-notebook-hub.online/sources/the-lens-scholarly-works.md) — Free search over 200M+ scholarly records with patent cross-links — unusual for connecting research papers to the inventions built on them. - [Unpaywall](https://gemini-notebook-hub.online/sources/unpaywall.md) — Looks up legal open-access versions of paywalled papers. Use it to locate a free PDF you can actually upload to Gemini Notebook. - [Web of Science](https://gemini-notebook-hub.online/sources/web-of-science.md) — Subscription citation index for tracing who cites whom across disciplines. Use it to build a reading list, then import the papers themselves.