Table 3 Variables used for scientific literature and patent searching
From: Assessment of technological level of stem cell research using principal component analysis
Variables | Definition |
|---|---|
Scientific literature | Â |
 Database | Scopus |
 Document type | Primary research articles |
 Subject areas | Life sciences and health sciences |
Patent | Â |
 Database | Focust |
 Patent type | Patents issued by the United States Patents and Trademark Office |
Search formula | Â |
 Adult stem cell | “Adult stem cell*” or [(hematopoietic or neural or mesenchymal or intestinal or pancreatic or retinal or Epidermal or “umbilical cord blood” or mammary or endothelial or olfactory or “dental pulp derive”) and “stem cell*”] |
 Embryonic stem cell | “Embryonic stem cell*” |
 Induced pluripotent stem cell | “Induced pluripotent stem cell*” or (iPS and “stem cell*”) |
Miscellaneous conditions | Â |
 Date range | Jan-01-1993–Dec-31-2012 (20 years) |
 Country | Canada, China, France, Germany, Israel, Japan, Singapore, Korea, Taiwan, United Kingdom, United States |