Perhaps you should try some spelling variations:
"cronicas americanos de medicina interna ;" » "cronicas americanas de medicina interna ;", "colonias americanas de medicina interna ;", "chicas americanas de medicina interna ;", "cronicas americana de medicina interna ;"
"tropico americano en medicina internet ;" » "tropico mexicano en medicina internet ;", "subtropico americano en medicina internet ;", "clasico americano en medicina internet ;", "tropico americano en mediante internet ;", "tropico americano en medicina integral ;", "tropico americana en medicina internet ;", "tropico americano la medicina internet ;"

Try widening your search to All Fields.

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (("cronicas americanos de medicina interna ;") or ("tropico americano en medicina internet ;"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("cronicas americanos de medicina interna ;") OR ("tropico americano en medicina internet ;")).
• Removing quotes may allow a broader search: (( cronicas americanos de medicina interna ; ) or ( tropico americano en medicina internet ; )).
• Adding a wildcard symbol may retrieve word variants: (("cronicas americanos de medicina interna ;") or ("tropico americano en medicina internet ;"))*.