Table 4.
Type of document.
| Document Types | n |
|---|---|
| Article | 4015 |
| Meeting abstract | 605 |
| Proceeding paper | 357 |
| Review | 288 |
| Book review | 237 |
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.