| Advanced Image Search Google - Search for images using text descriptions. |
| Bielefeld Academic Search Engine - More than 100 million scientific documents, 70% of them are free |
| Bing - Microsoft Bing online search |
Bioline International - is a library of scientific bioscience journals published in developing countries. |
| Dogpile - Dogpile returns all the best results from leading search engines including Google and Yahoo! |
| DuckDuckGo - Private Search - Search the Web without being tracked |
| Internet Archive is a non-profit library of millions of free books, movies, software, music, websites, and more. |
| PDF Drive - is the largest website for free download of books in PDF format. Claiming over 225 million names. |
refseek* - Academic Resource Search. More than a billion sources: encyclopedia, monographies, magazines. |
RePEc (Research Papers in Economics) - 4 million publications on economics and related science. |
| Science.gov - is an American state search engine on 2200+ scientific sites. More than 200 million articles are indexed. |
SpingerLink - access to more than 10 million scientific documents: books, articles, research protocols. |
WorldCat - a search for the contents of 20 thousand worldwide libraries. Find out where lies the nearest rare book you need. |
| FreeMapTools - An online resource that enables visitors to easily and quickly use maps for measure, search, overlay etc. |
| FreeMapTools - Elevation - This tool can be used to find an estimate for the elevation of a point on the earth. |
