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Tips to use our scientific article search engine

Advanced Search Engine

The aim of’s scientific article search engine is to increase the visibility and ease of use of open access scientific journals, theses, posters and patents. All scientific subjects are covered and all content are freely available in PDF format.
FreeFullPDF performs full-text search in PDF files (title, abstract, authors, materials and methods, results, conclusion, bibliographies…). With FreeFullPDF, you can easily and quickly find the scientific information you want through more than 100 million PDF files.

Search tips

The OR operator

FreeFullPDF ‘s default behavior is to consider all the words in a search. If you want to specifically allow either one of several words, you can use the OR operator.
Example: DNA sequencing OR sequencer

Terms you want to exclude (-)

Attaching a minus sign immediately before a word indicates that you do not want pages that contain this word to appear in your results. The minus sign should appear immediately before the word and should be preceded with a space. The – sign can be used to exclude more than just words.
Example: DNA sequencing -proteins -peptides

Phrase search (” “)

By putting double quotes around a set of words, you are telling FreeFullPDF to consider the exact words in that exact order without any change.
Example: “DNA Sequencing by enzymatic method”

Fill in the blanks (*)

The *, or wildcard, is a little-known feature that can be very powerful. If you include * within a query, it tells FreeFullPDF to try to treat the star as a placeholder for any unknown term(s) and then find the best matches.
Example: “DNA Sequencing by * method” will give you DNA sequencing by dideoxy method, DNA sequencing by the Sanger method, DNA sequencing by ligation-mediated PCR method, DNA sequencing by hybridization method …

Search in title

If you include [intitle:] in your query, FreeFullPDF will restrict the results to documents containing that word in the title tag.

Scientific Synonyms

Users’ search queries are automatically expanded with synonyms/acronyms.
Example: Search query “DNA” has the following equivalent alternatives: “deoxyribonucleic acid”, “desoxyribonucleic acid ” or “ADN”

Why is the number of results sometimes only approximate?

It is not always possible to know immediately following a search exactly how many results will be displayed by our scientific article search engine. In such cases, an approximate number is given, which is generally slightly higher than the actual number of results. This approximate number might change as you go through the results pages.