[Source: This article was published in aofirs.org By Erin R. Goodrich – Uploaded by the Member of Broadreader]

A PDF Search Engine or website is an Internet tool that crawls and searches all available PDF documents and indexes them in its database. When your search is particularly specialized, you will most likely need to use niche-specific search engines to get precisely what you are looking for in a more accurate and focused manner.

Several niche-specific search engines can assist you in your searches if you are a big fan of E-books and other documents typically published in PDF file formats – such as tutorials, instruction manuals, and other similar documents.

Here are some of the best PDF search engines list available on the web. These search engines will assist you in locating all of the numerous free e-books, tutorials, magazines, and other PDF files published on the Internet for free viewing and non-commercial reasons.

List of PDF Search Tools and Ebooks Downloads

Pdf Search Engine

PDFSearchEngine.net is a pdf search engine that assists you in searching free pdf books, e-books, and other pdf and MS Word files that are not easily searchable using other search engines. It is a Google Programmable Search Engine, assisting users in searching relevant pdf and MS Word documents for research or other needs.

Using PDF Search Engine is as simple as using other search engines like Google, Bing, and Yahoo. Simply type your query into the text box and press enter or the search button. It will be shown a list of search results relevant to your query.


You can use FreeFullPDF.com to identify and use open-source scientific articles, research papers, and posters that aren’t available in print or online. Everything you need to know about science is right here, and it’s all available in PDF format for free!

On Freefullpdf, there are around 80 million significant scientific documents. Ebooks on topics such as programming and biological sciences are available. You may also find ebooks results on a variety of topics. Google Custom Search Engine is now available for these web search engines pdf.



DocJax incorporates the world’s largest document search engine and the best place to go to get the documents you need. Docjax is a new online platform to search for PDF files and other types of pdf documents. You can find over 320,577 documents on 3,296 websites by searching for keywords. As a result, it’s a great place to start if you’re looking for ebooks online.

Search PDF with Google Advanced Search

If you want to find PDF files on Google (XLS files, DOC files, or any other format), you must know how to use specific Google search commands (Google Search Operators).

Google Search Operators are advanced search commands available on Google that can help you find what you’re looking for faster. One command is for locating files with a specified (kind) extension, such as PDF.

Let’s suppose that you want to search for a CIRS Certification Syllabus PDF. Follow these steps below.

  1. Go to GOOGLE
  2. On the search bar, type: filetype:pdf CIRS Certification Syllabus
  3. Press ENTER to search;

Now on the search results page, you can see multiple PDF files about CIRS Certification Syllabus, as exemplified in the image below:Google Advanced Search

If you want to learn advanced online search methods and techniques, the CIRS Certification training program is for you. The AOFIRS designed this course for those who want to learn advanced search queries for precision web search. You’ll learn about advanced search operators, as well as how to employ advanced Google methods to create powerful search queries.


You may use FileSearchBox to conduct a comprehensive search of the entire web for any publicly accessible PDF! It offers pdf downloads without requiring you to log in or do anything else. This search engine uses the Google index but limits its results to PDF files.



Ebook300 is the best site for finding and reading free ebooks by category and downloading links. There are over 34 different sorts of books for academic research. It also displays the book’s cover and other details before purchasing it.

Book Gold Mine

Book Gold Mine gives you free access to many high-quality ebooks, notes, lectures, and other publications. It includes business, biology, computer science, mathematics, and physics. Book Gold Mine can be helpful if you’re looking for a PDF file that fits into one of these categories.

PDF Geni

Pdf Geni is yet another excellent custom search engine for PDF files specializing in ebooks, manuals, catalogs, sheets, forms, and other PDF documents with a user experience identical to any other search engine.

You will stay anonymous to third parties because the server will not collect your Mac address, IP address, or any other information about you. When you search, they will collect information about your location and search terms to calculate the most often done searches worldwide.

PDF Geni


Free-eBooks.net is the most extensive collection of free eBook downloads, eBook resources, and eBook authors on the internet. The objective of FreeEbooks.net is to present you to fresh and independent authors, inventive writers, and even provocateurs who are willing to risk all for their art.

Before adding ebooks to your library collection, you can preview them for about 18 pages.


Bookboon is an eBook publishing company based in the United States of America. The organization’s primary goal is to publish instructional resources for business people. It is the largest ebook publisher globally, with 75 million free ebook downloads.

Bookboon specializes in two types of ebooks: student textbooks and business-related ebooks. This section provides over 1,000 PDF textbooks written by professors from the world’s most famous universities.

These textbook PDFs are available to students for free download. Bookboon’s business ebooks emphasize soft skills and personal development to assist readers in developing their business and professional skills.


PDF Drive

PDF Drive is a search engine for PDF files. They currently have 76,580,165 eBooks for free download. It is the go-to search engine for free PDF ebooks, periodicals, comics, and articles.

This website provides free PDF ebook downloads with no limits on how they can use them. Customers may access a vast collection of PDF search engines for ebooks in a single, easy-to-access area thanks to PDF Drive’s library, which is continually updated and expanded. Both PDF Drive and Library Genesis are fantastic options for professional ebook themes.

Search and Download PDF Files


Manybooks have an outstanding range of contemporary and classic literature waiting to be discovered. All are free and compatible with the vast majority of e-reader platforms. Manybooks has made an extensive library of free digital books available to users worldwide through the internet.

It has evolved into a platform for self-publishing authors to trade and publish new works, making it a more robust option than Library Genesis in this sense. This website focuses mainly on the fiction genre. The vast majority of books on Manybooks are available for free online reading or download in PDF format.

Many Books


PDF Books World library is an excellent source for free PDF books, which are digitized versions of books that have been designated as public domain.

PDFBooksWorld is a digital book publisher specializing in renowned historical authors such as Charles Dickens and Charles Dickens. PDFBooksWorld’s mission is to modernize these classic works by converting them to the PDF ebook format.



ScienceDirect is the world’s most comprehensive scientific, technical, and medical information academic search engine source. It explores academic journals, books, and articles. ScienceDirect is a website that provides access to the publisher Elsevier’s extensive bibliographic database of scientific and medical publications. It contains over 18 million pieces of content from this publisher’s more than 4,000 academic journals and 30,000 e-books.

ScienceDirect, like Library Genesis, helps researchers find answers to a wide range of questions, from fundamental science to cutting-edge research. Their database contains over 16 million articles and hundreds of ebooks and magazines, some as pdf book finders.


CALAMEO PDF Downloader

Calameo Downloader is a completely free tool that allows you to download any book or publication available on its site.

A free tool enables readers to download any book or publication available on Calaemo in a Pdf ebook form. Even though it publishes more than ten publications, this best pdf search tool is only compatible with Calameo Publications, enabling authors to obtain PDF versions of their works. If you do not see a PDF download link for this book, the author has not authorized its download from this site.



Obooko is a library of free books that anyone can use anywhere in the world. So, to begin pursuing that large assortment of fiction and nonfiction books, click the GET MY BOOKS button above. Then browse the category list for links to books that interest you.

Its online library contains the most popular free ebooks, which you can access at any time. It doesn’t matter which format you pick for each of the various ebooks. They will all download to your phone, tablet, laptop, or desktop computer in the format you select.

It’s also comforting to know that they don’t simply link to promotional books and novels on other websites all over the Internet. Because all titles are kept on their high-speed servers, you don’t have to leave Obooko to read online.


Internet Archive Books

The Internet Archive is a non-profit organization that provides free access to 20 million free ebooks, movies, software, music, and websites. In addition, anyone with a free archive.org account can access a collection of 2.3 million current eBooks.

When compared to Library Genesis, the Internet Archive Books collection contains a greater variety of books. The majority of the topics and subjects in the Internet Archive Books collection are available in over 100 languages, and they cover over 1,000 of them. This is the finest spot for out-of-print historical and intellectual literature and works.

Internet Archieve


Science.gov searches over 60 databases and 2,200 scientific websites to deliver over 200 million pages of reliable government science material in various formats, including full-text papers, citations, scientific data supporting federally supported research, and multimedia.

It also provides free access to journal articles, peer-reviewed accepted submissions, and reports on research supported by federal science agencies and the agencies’ public access rules and standards.


The BASE is a significant pdf search engine that focuses on academic websites. It has over 240 million documents from over 8,000 content providers. The complete texts of around 60% of the indexed publications are available for free open access. The Bielefeld University Library is in charge of the BASE.

The BASE index can be integrated into a database administrator’s infrastructure (for example. meta-search engines library catalogs). Numerous tools and services are available to users, administrators, database administrators, and repository administrators.


ResearchGate is one of the most extensive PDF search engines available to academics and researchers. It has about 135 million specialized papers on biology, computer science, medicine, physics, and social science.

It is a commercial social networking platform for scientists and researchers in Europe. Users can share papers, ask and answer questions, and work together on projects. ResearchGate is an online community of scientists and researchers.

Research Gate

Google Scholar

Google Scholar is an excellent resource for those who spend most of their time hunting for research papers. It allows you to do cross-disciplinary and cross-source searches from a single spot.

It can help you find theses, eBooks, academic publications, online repositories, abstracts, and other resources. Whatever your research topic, Google Scholar will help you uncover useful material.

eBook Lobby

eBookLobby.com is a library of free ebooks. It offers free ebooks in various categories, including business, art, computing, programming, and education. These are known as free ebooks, and some examples include business, art, and computers.



Find-pdf-doc allows you to conduct a thorough search of the entire internet to find ebooks & documents. AND IT’S ENTIRELY FREE! This search engine will enable you to download PDF, DOC, PPT, TXT, and SWF files.

If you’re looking for a specific ebook or PDF file, another pdf search engine is Find-pdf-doc. Other file types of search engines pdf supported in DOC, PPT, XML, RTF, AI, DWP, MP#, and many more. You can also find many files on this website.

Look for alternative specialized search engines that can return relevant results for your query fast and easily. You can find specialized search engines on our list of search engines.


How to search PDF on Google?

To search any PDF files, use the google search operator “filetype:pdf + Keyword”

For example, to find the PDF files for the search term ‘’Internet Research Paper’’ enter “filetype:pdf Internet Research Paper” in the search box. You will view all PDF files related to your search.

How to search in a PDF document?

When you open a PDF in Acrobat Reader or in a browser, the search window pane may or may notbe displayed. Use “Ctrl+F” to bring up the search/find window pane in a PDF document.