Table 5.
Most occurring keywords in the research on transplantation from the United States
| Keyword | Occurrences | Total link strength |
| Recipients | 3045 | 13158 |
| Survival | 2779 | 11573 |
| Outcomes | 2399 | 10308 |
| Rejection | 1792 | 7691 |
| Kidney transplantation | 1605 | 7823 |
| Mortality | 1501 | 6280 |
| Risk | 1497 | 6105 |
| Impact | 1490 | 6486 |
| Immunosuppression | 1484 | 7371 |
| Renal-transplantation | 1403 | 6297 |
| Therapy | 1347 | 4974 |
| Risk-factors | 1340 | 5482 |
| Infection | 1195 | 4580 |
| Children | 1154 | 4366 |
| Expression | 1083 | 3647 |
| Kidney-transplantation | 1080 | 4763 |
| Liver transplantation | 1020 | 3976 |
| Lung transplantation | 931 | 3809 |