Japan Patent Office (JPO)
http://www.jpo.go.jp/index.htm

World Intellectual Property Organization (WIPO)
http://www.wipo.int/portal/en/

European Patent Office (EPO)
http://www.epo.org/

United States Patent and Trademark Office (USPTO)
http://www.uspto.gov/

State Intellectual Property Office of the People's Republic of China (SIPO)
http://english.sipo.gov.cn/

Korean Intellectual Property Office (KIPO)
http://www.kipo.go.kr/kpo/user.tdf?a=user.english.main.BoardApp&c=1001

Taiwan Intellectual Property Office (TIPO)
http://www.tipo.gov.tw/mp.asp?mp=2

Japan Patent Attorneys Association (JPAA)
http://www.jpaa.or.jp/?cat=546

Japan Platform for Patent Information (J-PlatPat)
https://www.j-platpat.inpit.go.jp/web/all/top/BTmTopEnglishPage

PATENTSCOPE (WIPO)
https://patentscope.wipo.int/search/en/structuredSearch.jsfttp

Espacenet Patent Search (EPO)
http://worldwide.espacenet.com/advancedSearch?locale=en_EP

Patent Full-Text Databases (USPTO)
http://patft.uspto.gov/