Patents

Major search engines

EPO Patent Information on the Internet
Patents Information - Washington University Libraries

Organizations of industrial property 

Canada Canadian Intellectual Property Office (CIPO-OPIC)
Directory of  intellectual property organizations World Intellectual Property Organization (WIPO-OMPI)
European Patent Office EPO
France Institut National de la Propriété Industrielle (INPI)
Germany Deutsches Patent- und Markenamt (DPMA)
Portugal Instituto Nacional de Propriedade Industrial
Spain Oficina Española de Patentes y Marcas (OEPM)
UK UK Patent Office
USA U.S. Patent and Trademark Office (USPTO)

Patents Databases

Patent Databases on the Internet

Stanford University Libraries.

Directory of patents and intellectual property available online

USPTO Web Patent Databases

US Patent and Trademark Office.

Bibliograhic database and full text of US patents

WIPO

World  Intellectual Property Organization (WIPO)

It collects patent information at international level, in accordance with the international treaty on patent co-operation, whereby all countries in the world that are members of WIPO are obliged to deposit the bibliographic reference with a summary of the patents registered in each of them.

Reference works

Glossary of Patent Terms Glossary (Delphino)
Marcas  Guides to trademarks (MicroPatent)
Patentes Guides to Patents (MicroPatent)

Information about Patents

Intellogist

Portal that provides information and educational material to those who make searches on patents 

Intellogist blog Blog that provides information on patent
Twitter @Intellogist