Perhaps you should try some spelling variations:
"cronicas americanas de medicina interna ;" » "colonias americanas de medicina interna ;", "chicas americanas de medicina interna ;", "cronica mexicana de medicina interna ;", "cronicas americanas del medicina interna ;", "cronicas americana de medicina interna ;", "cronicas americanos de medicina interna ;"
"tardes americanas en medicina interna ;" » "tales american en medicina interna ;", "tardes americana en medicina interna ;", "tardes americanos en medicina interna ;", "tardes americano en medicina interna ;", "tardes americanas la medicina interna ;"

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 americanas de medicina interna ;") or ("tardes americanas en medicina interna ;"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("cronicas americanas de medicina interna ;") OR ("tardes americanas en medicina interna ;")).
• Removing quotes may allow a broader search: (( cronicas americanas de medicina interna ; ) or ( tardes americanas en medicina interna ; )).
• Adding a wildcard symbol may retrieve word variants: (("cronicas americanas de medicina interna ;") or ("tardes americanas en medicina interna ;"))*.