Sorry, the above-mentioned corpora are only accessible to research teams here and Tokyo University (the project collaborator). But, don't be disappointed. As they are built on the text archives from MEDLINE, you may want to have a look at MEDLINE online database:
MEDLINE
Compiled by the U.S. National Library of Medicine (NLM) and published on the Web by Community of Science, MEDLINE® is the world's most comprehensive source of life sciences and biomedical bibliographic information. It contains nearly eleven million records from over 7,300 different publications from 1965 to today. MEDLINE® is updated weekly.
MEDLINE® through COS enables you to:
-- Search interfaces for all experience levels;
-- Link from MEDLINE® abstracts to information in other biological databases;
-- Search or Browse Medical Subject Headings (MeSH);
-- Search by specific medical journals;
-- Download search results in a variety of formats, including EndNote and Reference Manager;
-- Access COS Query Track, which allows you to save your searches from each session and quickly repeat them in future sessions.
http://medline.cos.com/
Good luck!