Perhaps you should try some spelling variations:
"cronicas americanos de medicina interna ;" » "cronicas americanas de medicina interna ;", "chicas americanas de medicina interna ;", "clasicos americanos de medicina interna ;", "cronicas americana de medicina interna ;", "cronicas americano en medicina interna ;"
"colonias americanas de medicina internet ;" » "colonias agricolas de medicina internet ;", "colonias americanas de mediante internet ;", "colonias americanas de medicina integral ;", "colonias americanas del medicina internet ;", "colonias americana de medicina internet ;", "colonias americanos del 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 ("colonias americanas de medicina internet ;"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("cronicas americanos de medicina interna ;") OR ("colonias americanas de medicina internet ;")).
• Removing quotes may allow a broader search: (( cronicas americanos de medicina interna ; ) or ( colonias americanas de medicina internet ; )).
• Adding a wildcard symbol may retrieve word variants: (("cronicas americanos de medicina interna ;") or ("colonias americanas de medicina internet ;"))*.